Notices of Memoirs—Cambrian of Baltic Provinces. 421 
the centre and at the lateral angles these scale-markings become 
much larger, more acutely pointed in shape, and more irregularly 
distributed. 
These scale-markings agree exactly with those of Hurypterus 
Mansfieldi (Hall), as represented by Prof. Hall on an enlarged scale 
(see plate v. fig. 6, op. cit. p. 88), but the margins of the segments 
of the Radstock specimen are hardly so pointed at their latero- 
posterior angles as the American species above quoted. The pro- 
portions are about equal to the largest example recorded by Prof. 
Hall. 
In the absence of the rest of the organism, it would be premature 
to speak confidently ; but, as it will probably prove to be a distinct 
British species, but near to H. Mansfieldi of Hall, I would propose 
to name it provisionally Hurypterus Wilsoni, after its discoverer. 
NOTICES OF MEHMOTRS. 
CamBRIAN Fauna IN ESTLAND. 
UEBER EINE NEUENTDECKTE UNTERCAMBRISCHE F'AuNA IN ESTLAND. 
Von F.Scumipr. Mit zwei Tafeln. (Mem. de l’Acad. des Sciences 
St.-Pétersbourg, vii® série, tome 36, 1888, pp. 1-28, pls. i. ii.) 
ITHERTO the Cambrian strata of the Russian Baltic provinces 
have proved so exceedingly poor in fossils, that it has not 
been possible to make a satisfactory comparison between them and 
the relative beds in Sweden and elsewhere. Below the Dictyonema 
shales, which are analogous to the beds of the same name in Norway 
and Sweden, there occurs the Unguliten or Obolus sandstones ; and 
beneath these are beds of blue clay with subordinate layers of sand- 
stone, which rest upon Finland granite, and have been proved by 
borings to reach 600 feet in thickness. The upper portions of the 
blue clay series in Estland were regarded by Linnarsson in 1872 as 
equivalent to the Hophyton sandstone of Sweden, and the main mass 
of the Unguliten sandstone as representing the Fucoid sandstone of 
the same country; but at that time no fossils were known which 
could substantiate these views. Lately, however, thanks to the 
persevering efforts of M. Mickwitz, an engineer of Reval, the frag- 
mentary remains of a characteristic fauna have been discovered in 
the upper beds of the blue clay series at Reval and the neighbour- 
hood, which fully confirm Linnarsson’s opinions. The fossils 
which have been carefully described and figured by F. Schmidt in 
the present paper are Olenellus Mickwitzi, n.sp., Scenella discinoides, 
n.sp., S.? tuberculata, n.sp., Mickwitizia (Obolus?) monilifera, Linnars. 
sp-, Obolella (?) sp., Discina (?) sp., Volborthella tenuis, n. gen. et sp., 
Platysolenites antiquissimus, Kichw. sp., Medusites Lindstreemi, Linuars. 
sp., Primitia?, Cruziana, and Frena tenella, Linnars. 
The Olenellus Mickwitzi comes in at a lower stage than the O. 
Kjerwfi, and is thus the oldest Trilobite known in Europe. Its 
occurrence at this horizon confirms the views of Linnarsson, Holm, 
and Brogger, that the Olenellus zone is distinctly older than that of 
Paradouides. 
