118 The American Geologist. February, 1902. 
to trace the basal conglomerates as the starting point of the Cambrian 
succession, there, and in other parts of the world. 
Frech remarks upon the rarity of fossils in these conglomerates, 
and the difficulty of determining the part of the Cambrian which they 
represent, but he seems to assume that they are below the Olenellus 
Leds which he takes as the oldest fossiliferous Cambrian zone. 
He proceeds to show how this is developed in the (a) Marine 
Basin of the Rocky Mountains and gives a list of the genera which 
he supposes to characterize it; also (b) the North Atlantic Sea with a 
far more numerous and varied suite of genera; also (c) the Punjab 
in India, distinct by its dolomytes and salt deposits. 
The land areas of the Lower Cambrian are then considered with 
proofs of the existence of an Algonkian and Arctic and a Middle 
European continent. These are determined by the way in which the 
Lower Cambrian overlaps upon the older formations. 
In Middle Cambrian there were advances of the sea upon the land, 
in some countries, but in others a retreat of the ocean; an advance of 
the sea into Poland, also along the east coast of the British provinces, 
but retreat from the St. Lawrence valley; also he considers that the 
connection with the Arctic sea, existing in the Lower Cambrian time 
was now broken up. 
Then there was the Mediterranean European overlap of the sea 
extending to Bohemia in the north and to Languedoc and Spain in the 
west. This Prof. Frech claims to have been an extension of a 
Sardinian Olenellus sea. 
Dr. Frech also postulates a Pacific ocean of the Cambrian time 
on account of the absence of Paradoxides from all parts of its borders 
and the wide distribution of Olenellus. He calls attention also to 
the occurrence of Dorypyge (Olenoides quadriceps) both with Olenel- 
lus and with the middle Cambrian genera in that region. 
The author then goes on to discuss the Upper CAMBRIAN and its 
distribution, in relation to possible land areas specially referring to 
the withdrawal of the sea from the middle European areas, and the 
remarkable overlap of the ocean on large areas of the North Amer- 
ican continent; thus were separated the Olenus fauna of the Atlantic 
coast, and the Dicellocephalus fauna of the interior. “This may have 
been the first upward arching in the region of the Appalachian.” 
Frech remarks that the beds of southern Europe which have been in- 
terpreted as Upper Cambrian, are the equivalent of the Tremadoc; 
therefore according to his view not Cambrian. He appears to de 
scribe the Paradoxides bed of Massachusetts as equivalent to the Par- 
abolina and Dictyonema bed of the Acadian provinces, but this may 
not be his meaning. 
The remarkable uniformity of the Potsdam sandstone as a shore 
deposit of Upper Cambrian age is something remarkable; it is like 
the feeble coast formation of the Obolus sandstone along the north- 
ern shore of the Scandinavian Cambrian sea. The Upper Cambrian 
horizon is shown by the Dictyonema beds of Belgium and Wales, and 
