134 Revieus — Baron von Toll — The Siberian Cambrian. 



as of Devonian, Carboniferous, and Triassic age. The strata are 

 principally exposed in tlie banks of the great rivers, and fossils 

 have been found in the following localities : (1) Torgoschino, near 

 Krasnojarsk on the Yenesei, 56° N. lat., 93° E. long. ; (2) on the 

 right bank of the Vilyui, 63° N. lat., 115° E. long. ; (3) on the 

 Olenek, in 70° N. lat., 120° E. long.; and (4) on the Lena, 

 between Oleminsk and Yakutsk, in 64° N. lat., 128° E. long. 



From limestones on the Lena the author describes two species of 

 Ptychoparia related to forms in the Olenellus zone of North America ; 

 three new species of Microdiscus, two of which approach closely to 

 American forms; Agnostiis, sp.n.; fragments of a doubtful Olenellus; 

 Kutorgina cingulata, Billings ; an Obolella related to 0. chromatica, 

 Bill. ; and an undetermined Hyolithes. 



The beds on the Olenek contain BatJiyuriscus Howelli, Walcot, 

 a Middle Cambrian species found originally in Nevada ; Agnostiis 

 CzeTcanowslcii, Fr. Schmidt ; and some worm tracks. From the Vilyui 

 Fr. Schmidt has already described Anomocare Fawlowshii and 

 Liostracus ? Maydelli. 



From limestones at Torgoschino on the Yenesei two species of 

 Trilobites, Proetus SlatkowsMi and Cyphaspis Sibirica, had been 

 described by Fr. Schmidt : the former of these is now determined 

 by the author to belong to the Cambrian genus Dorypyge, Dames, 

 and the latter with some doubt to Solenopleura, Angelin. 



The Yenesei rocks likewise contain numerous representatives of 

 the widely distributed Cambrian family of the Archfeocyathinaa. 

 The author describes six species of Archceocyathus, Bill., three of 

 which are new, and three considered to be identical with species 

 from the Cambrian rocks of Sardinia. Of the allied genus Coscino- 

 cyaihus, Bornemann, seven species common to the Sardinian rocks 

 and one new are recognized, and there is also a doubtful form of 

 JProtopharetra, Bornemann. The Yenesei examples of this family, 

 like those from Sardinia, appear to be enclosed in a very hard lime- 

 stone, so that they can be studied only in sections ; consequently 

 the recognition' of specific characters is very difficult, and complete 

 identification of species^ as the author acknowledges, is hardly to be 

 expected. 



A new genus, Bhabdocyathiis, is also proposed : it agrees, in the 

 laminate character of the wall, with Spirocyathus, Hinde, but it 

 possesses neither septa nor dissepiments, and the space between the 

 inner and outer wall layers is traversed by tubes which open on the 

 exterior surface as rows of pores. The author considers that this 

 form represents a simpler type of the family than any hitherto 

 known, and, further, that it furnishes a clue to the systematic 

 position of the group, which, as is well known, is not as yet by any 

 means settled. The Archeeocyathinai have been in turn referred to 

 siliceous sponges, foraminifera, and perforate corals, but their 

 resting-place in any one of these divisions has not received the 

 general support of palaeontologists. Von Toll puts forward a fresh 

 suggestion, namely, that they are possibly Calcareous Alga3, whose 

 nearest relations are to be found in the Tertiary genus Acicularia, 



