172 Notices of Memoira — Trias in the Caucasus. 



characteristically represented in his collection ; and an entirely new 

 contribution to the geology of the Caucasus results from that part of 

 Worobiev's materials, which has been worked out by Dr. Cernysev, 

 who described the Brachiopods, and by A. A. Borisiak, his colleague 

 on the Geological Committee of Russia, who identified the Pelecypods. 



The starting-point of Worobiev's expedition was from Psebai, on 

 the Little Laba River, whence he proceeded to the source of the Khods 

 River (a left tributary of the Little Laba), where he pitched his first 

 camp. From this place he made a series of excursions in different 

 directions, resulting in an interesting collection of Triassic material. 



On the very first excursion, which was undertaken along the Khods 

 River, 3 versts from the camp, in the Mietok Ravine, Worobiev found 

 a small exposure of limestone crowded with valves of PseuAomonotis 

 ocliotica, Keyserling ; and again lower down the gorge, in the same 

 limestone, he observed great quantities of Terehratida pyriformis, Suess, 

 Waldheimia cuhanica, n.sp. (somewhat recalling W. norica, Suess), 

 W. {Cruratuld) lahensis, n.sp. (near to but undoubtedly distinct from 

 W. {C.) BeyrieM, Bittn.), and Amphiclinodonta Katzeri, Bittn. 



The third excursion was in a southerly direction towards Mt. Tkhach ■ 

 2 versts beyond the ford across the Khods River "Worobiev investigated 

 limestones extremely rich in Brachiopods ; still further on these lime- 

 stones continued, but Avithout clear exposures. In these Brachiopod 

 limestones he found the following forms : — Terehratida turcica, Bittn., 

 T. pyriformis, Suess (abundant), Spiriferina aff. Jcossene^isis, Zugm., 

 S. Suessi, Winkler, Spirigera culanica, n.sp., >S'. oxycolpos, Emmr., 

 Ret%ia superlescens, Bittn., Rhynchonella fissicostata, Sness, JR. aff. Jissi- 

 costata, Suess, R. afl. anatolica, Bittn., R. lahensis, n.sp., R. Worohieffi, 

 n.sp., Amphiclinodonta Suessi, Hofm., and other less well-preserved 

 forms. 



Subsequently his journey was directed towards the upper Sokhra 

 River, belonging to the system of the Bielaj^a River. At 5 versts from 

 Mt. Tkhach, towards the left feeder of the Sokhra, he met with 

 a complete section of the Triassic limestone, dipping 15°-25° jS^.E., 

 showing the following downward succession: — 



1. Red and grey limestone, with Pseudomonotis ochotica, Keyserling. 



2. Red, more compact limestone, with P. ochotica, Keyserling, and 

 the following Brachiopods: — T. pyriformis, Suess, W. aff. norica, 

 Suess, W. [Aidacothyris) &&. fro^itaiis, Bittn., W. {A.) reflexa, Bittn., 

 Spiriferina Suessi, Winkler, Spirigera Worolieffi, n.sp. (undoubtedly 

 belonging to the same group as S. oxycolpos and S. 31an%avinii), 

 S. oxycolpos, Emmr., var. caucasica, n.var., Retzia superbescens, Bittn., 

 Rhynchonella levantina, Bittn., R. Fuggeri, Bittn. 



3. Grey limestone with Crinoid fragments,^ and the Brachiopods 

 W. {A.) reflexa, Bittn., R. superbescens, Bittn. 



' With regard to this Crinoidal limestone it may be of interest to draw attention 

 to the fact that Dr. Eadde in one of his journeys in this region of the Caucasus very 

 nearly anticipated by about thirty years Worobiev's discovery of these Triassic strata, 

 for in the Tiflis Museum {Die Sammhmgcn des kaukasischen JIuseiniis, iii, Geologie, 

 p. 171) there is a specimen collected by Dr. Radde from this very district, viz., 

 from the "river-bed of the Matchubusta, a tributary of the Khod river, near 

 Mt. Tkhach".— F. 0. 



