282 CARNEGIE INSTITUTION OP WASHINGTON. 



Blackvvelder, in December, carried out instructions for a recounois- 

 sance to cover the point. The Yung-ning sandstone described by 

 Baron von Richthofen was found, but contains no fossils and is strati- 

 graphically probably not older than the lowest Cambrian of Shantung. 



In Chihli and Shansi, north of latitude 38°, Cambrian strata very 

 similar to those in vShantung were discovered. Their general rela- 

 tions and sequence were observed and their occurrence noted in 

 connection with topographic surveys, so that the areas can be repre- 

 sented in a general way on the maps. Fossils were secured which 

 suffice to identify the Lower, Middle, and Upper Cambrian terranes. 



In southern Shensi, about latitude 31° 30', occur limestone strata 

 several thousand feet thick, which are but sparsely fossiliferous. In 

 river pebbles derived from them fragments of Olenellus were found, 

 which proved that the older strata are Lower Cambrian. Unfor- 

 tunately the beds did not appear along the route traveled, but the 

 limestones so closely resemble those of Middle and Upper Cambrian 

 age of Shantung and Shansi in certain unusual lithologic characters 

 as to leave little doubt of their being part of a corresponding sequence, 

 at the base of which the Olenellus occurs. 



Cambrian Glacial Deposits . — On the Yangtse River, in latitude 31° — 

 z. e., as far south as New Orleans, not high above sea-level — a large 

 body of glacial till was discovered. It is unstratified, a mass of 

 indurated clay and heterogeneous bowlders, many of which exhibit 

 glacial polish and striae. Specimens submitted to Professor Cham- 

 berlin and other expert glacialists are pronounced by them unques- 

 tionably of glacial origin. This deposit lies near the base of the 

 Paleozoic system, beneath limestone which in its lowest layers 

 contains pebbles from the till, and which is in all probability of 

 Lower Cambrian age, as the specimens of Olenellus referred to in 

 the preceding paragraph were found in this district. The body of 

 till is 170 feet thick, a ver}^ considerable mass. It demonstrates 

 the existence of glacial conditions in a very low latitude in the early 

 Paleozoic. A similar occurrence at a closely related Cambrian epoch 

 has been reported from Scandinavia, but nowhere else has like evi- 

 dence been found. This discovery takes a place among'the unique 

 facts of geological history, and the latitude, the conditions of occur- 

 rence, and the conclusiveness of the evidence being considered, it 

 will have great weight in reference to theories of climatic change. 



Ordovician Strata. — Throughout Shantung, Chihli, Shansi, and 

 Shensi, between latitude 30° and 40°, there is a limestone 3,000 

 feet or more thick, which is stratigraphically continuous with the 



