190 Geology of the Bosphorus. 
remarkable species. The three specimens found by us at Geuk- 
son are fully equal to the one given in his plate. 
Almost all the fossils of this part of the Geukson Valley are 
very large and peculiar to the locality. The Spirier exists 
everywhere, especially the Spirifer subspeciosus. The same 
may be said of the several varieties of Plewrodyctium especially 
the problematicum and Constantenopolitanum ; also of several 
species of Oyathophyllum. Many varieties of Orthoceras and 
Trochoceras are found at Arnaoutkuei and Caudlijah ; a few at 
' Baltaliman and Geukson. We have found in all ten or twelve 
species, the names of most of which we do not know, but 
among them is the Zrochoceras Barrandei of de Vernueil, which 
is probably a misnomer; it is probably a Lituites. The species 
of Orthis are found in all the localities, but most sbupaas 
in abundance; at Baltaliman it is hardly found at all. The 
Pterinea elegans also is common at Caudlijah and Geukson, but 
is not found at Baltaliman. Rhynconella, Strophomena and 
Chonetes and species of other genera abound in various locali- 
ties. Crinoids and corals of many kinds, and some of them of 
great beauty, occur at all the points mentioned. Should we 
have the good fortune to receive a visit from some thoroughly 
competent paleontologist, we shall submit the Robert College 
collection to his consideration and publish a full catalogue of 
our specimens. At present there are many which we cannot 
determine. 
vast collections of conglomerate of every kind of coarseness; 
often composed of masses of black doleritie porphyry with other 
forms of rock which are very difficult to determine. These 
are often regularly stratified, but in other localities in immense 
masses, broken only by irregular fractures. | | 
.s there is no visible crater from whick all these rocks could 
have been thrown out, nor indeed anything which looks like 4 
