Tertiary Deposits* 119 



curring. The former has, in many parts, the very same 

 structure and contents as the London clay. Sections are 

 seen of beds equivalent to the calcaire grossier and London 

 clay, in connexion with strata referred to the upper part of 

 the cretaceous system. In the neighbourhood of Saratof, on 

 the Lower Volga, there occurs a sandy calcareous gint, sub- 

 ordinate to clay and sand, of a concretionary structure, un- 

 distinguishable from the Bognor rocks in Sussex, and con- 

 taining the same shells. The authors appear inclined to 

 believe, that an insensible gradation may be traced from the 

 upper cretaceous into the tertiary beds. 



The Miocene deposits are of far greater extent than the 

 Eocene. They are the extension of the great basins of Vien- 

 na and Hungary, and are spread over Volhynia, Podolia, and 

 Bessarabia, stretching to the Black Sea and the country 

 north of Odessa, where they are covered by deposits of a 

 more modern age. They have a close affinity to the deposits 

 of the sub-Apennines and of Bordeaux, and like beds of the 

 same age in Styria and Hungary, contain extensive oolitic 

 beds, undistinguishable, lithologically, from many English 

 and French varieties of the Jurassic group. 



Marine Pliocene deposits are wanting, but the Miocene are 

 covered by the vast deposit of argillaceous limestone already 

 referred to as occupying the region around the Caspian, called 

 by Sir R. Murchison the Aralo- Caspian or Steppe limestone, 

 in which the univalves are of fresh-water origin, associated 

 with forms of Cardiaceoe and Mytili, which are common to 

 partially saline or brackish water. It abounds in many places 

 with fresh -water shells, and indeed presents the true and per- 

 sistent characters of a deposit in an inland sea, and contains 

 no vestiges of corals or other marine bodies. It was ob- 

 served to be in some places between 200 and 300 feet thick, 

 and at elevations of 700 feet above the present level of the 

 Caspian. It possesses an uniformity of character which se- 

 parates it from any tertiary deposit of Western Europe. 



You are aware that Mr Lyell read before this Society four 

 papers on the tertiary deposits of the United States, which 

 have been published in our " Proceedings ;" it is unnecessary, 

 therefore, for me to give even a brief summary of them, and 



