The article goes on to advance a hypothesis about the formation of the Syukeyevo caves: “Flint, calcite, and gypsum are washed out by water, giving the limestone a porous appearance, sometimes leaving large voids, which are often filled with sulfur and petroleum deposits. Perhaps the caves, which are frequently encountered in this limestone, were originally formed from these same voids; the vaults of such caves are rounded by the action of water, which probably also widened them, washing out the concretions of gypsum, and perhaps also rock salt, for we have found grains of it in overlying gypsum. Both the vaults and the walls of the caves are covered with petroleum, sulfur, or calcareous nitrate, whose formation could also promote the widening of the caves.... The floors of the caves are often covered with water, for the Volga floods them in the springtime; aside from this, they have their own small springs with petroleum and sulfur.” It also drew attention to the fact that “the lower layer of limestone, located almost on the Volga’s summer water table, is the richest in such springs; whereas they are almost completely dried up in the upper strata, leaving behind a hardened mineral tar filling all the cracks and voids.” The geologists also noted the primitive methods used by the local population to recover petroleum for household and medicinal purposes: “Such water, coming to the surface in springs, is used as medicinal water, for baths and to be taken internally. The inhabitants of the district collect petroleum for their own needs by digging out small holes in front of the source of a gushing spring; these holes fill with water, and petroleum floats on the surface; this petroleum is then removed.”
Several years later, the Mining Department sent another expedition, this time with the specific goal of prospecting for bituminous minerals in the Volga region. In 1837, Gorny zhurnal published the “Report of Staff Captain Gerngros II on Prospecting Carried Out at the Direction of the Mining Authorities in the Sibir, Kazan, and Orenburg Regions to Discover Asphalt Deposits.” In this work, mining engineer Aleksandr Gerngros described the deposits of useful minerals in the Volga region in detail. He gave a detailed description of the territories he had studied, their geologic structure, their nature and soils, as well as descriptions of the Zhiguli Mountains, the Syukeyevo cave (16.5 miles from the city of Tetyushi), and deposits of various useful minerals 6.6 miles from the city of Syzran, near the village of Karpara.
It should be noted that a large part of his report was also devoted to natural asphalt. He described deposits of asphalt near Kostichey in Pustylny Gorge, close to the city of Tetyushi, around the village of Pechorskoye, in the village of Troyekurovka, on the right bank of the Volga, at the point where the Syzranka River discharges into it, near the city of Syzran, etc. He performed mineralogical tests of the asphalt directly on site: “The tar’s color is brown on the surface, black when fractured. It has a glassy luster and is extremely light and brittle. It melts and runs when exposed to fire, similar to pitch, giving of an odor of black sealing wax; it does not catch fire easily, and quickly goes out.” About the product of another deposit he wrote: “Its entire mass is of a black color, together with a resinous odor similar to that of tar.” Staff Captain Gerngros also noted a curious fact regarding the use of asphalt by the local population: “Near the village of Kostichey, where the viscous asphalt is encountered to a greater extent than elsewhere, blacksmiths use it for bluing iron products, which protects them from rust and gives them a more pleasant appearance.” In his report, Gerngros also pointed out the location of a series of petroleum deposits: “Petroleum of various thickness and of a blackish-brown color was noted near the city of Tetyushi and the village of Sergiyevsk and 10 versts [6.6 miles] from the sulfur waters. Between Tetyushi and Syukeyevo village, it comes out of rock faces and impregnates chalky marl.... But the most interesting petroleum deposit is located five versts [3.3 miles] from the village of Novoyakushkino, 200 sazhens [1,400 feet] from the mountain called Sarzhat. In a pit three feet deep and four feet wide, water is covered on the surface with black and very sticky petroleum, and although it is rather frequently skimmed off, within several days it accumulates again.”
On the basis of his observations, mining engineer Gerngros drew important scientific and theoretical conclusions. In his report, he noted that “the asphalt sediments found in cracks of chalky marl, all the more so in its lower parts, suggest that at the present time they form from resinous particles that combine through some chemical process, and that the main deposit of it is hidden in the Earth’s rocky crust.” Thus, Aleksandr Gerngros simultaneously stated two very important theoretical principles. First, that the asphalt deposits in the Volga region are secondary and arose as a result of the migration of a more liquid product from the depths of the Earth to the surface layers. And second, that asphalt forms from more liquid resinous parts as a result of chemical processes—that is, as a result of petroleum oxidation. Even today, these principles formulated by mining engineer Gerngros coincide with the views of contemporary geology scholars regarding the formation of natural asphalt and petroleum deposits.
Unfortunately, Volga entrepreneurs did not make use of the impressive results of Staff Captain Gerngros’s expedition to develop the oil business. However, 18 years later, when mining engineer Aleksandr Gerngros was appointed to the high post of director of the Department of Mining and Salt Works, he revisited the question of resuming petroleum prospecting in the Volga region.
This mission was assigned to the well-known Russian geologists Gennady Romanovsky and Pavel Yeremeyev, who were officers of the Corps of Mining Engineers. Over almost seven seasons (1863–1868), Corps of Mining Engineers Captain Gennady Romanovsky (1830–1906) made a detailed study of the sites of surface oil shows in the region of the Urals and the Volga, in the region of the cities of Buguruslan and Bugulma between the Sok and Kinel Rivers, and also in the regions lying south of Kinel. Having discovered oil shows at the Nizhnyaya Karmalskaya station in the Sheshma River valley, he drew the following conclusion: “There is no doubt that the rocks lying underwater contain cracks through which petroleum and gases escape.” In the villages of Sarabikulovo and Shugurovo he found oil, where “certain waters containing drops of petroleum point, without any doubt, to the presence of liquid petroleum inside the strata.” At the village of Staraya Semenkina mining engineer Romanovsky found sandstone that had previously been impregnated with petroleum, with a thick tar flowing out of the surface of the sandy sheets being heated by the sun. He also discovered petroleum at the village of Kamyshla. In this connection he wrote that “near the city of Tetyushi, around the source of the Cheremshana River, which flows into the Volga opposite the city of Singaleni, and also at the headwaters of the Sok River, close to the Sergiyevsk mineral waters, there are traces of petroleum sources.” Concerning the origin of the petroleum deposits he had discovered, Corps of Mining Engineers Captain Romanovsky announced in quite definite terms: “The mineral oil of Samara Province flows out of layers of Devonian or Lower Carboniferous soil.” In so doing, he made an important discovery that determined the future nature of prospecting in the region, as he had established that the petroleum contained in sediments of Permian age also served as a sign of “rich underground accumulations of it [mineral oil].” Developing this thought, he wrote: “I am completely certain that in Samara Province basins of liquid petroleum are definitely confined under Permian sandstones.... The petroleum must originate in Devonian sediments, and consequently at a depth of less than 100 sazhens [700 feet].”