RECORDS. 677 



Manhattan Series ; in not a single case has a hornblende schist 

 been observed to cross the other beds. If one or all of these 

 are dikes, the lamination of the associated beds must also have 

 been effected by a general shearing. But the series is accepted 

 as typically metamorphic, a succession of true beds of altered 

 sandstone (quartzitic gneiss), shales (mica schist), magnesian 

 schists (dolomite marble), etc., into which the injection of trap 

 dikes exclusively between the beds would be entirely improbable. 

 These hornblende schists, moreover, on Morningside Heights, 

 as elsewhere, thin out along the strike like the Other lenticular 

 beds ; often become partially- or entirely biotitic and quartzose ; 

 passing gradually into biotitic schists, biotitic" and hornblende 

 gneisses, exactly like those of acidic constitution which enclose 

 the above supposed dike. Indeed a basis element rich in Hme 

 and magnesia, is distributed throughout the Manhattan Series, 

 and was originally perhaps hornblendic throughout, or, in the 

 absence of silica, concentrated in the numerous dolomite beds. 

 The more purely hornblendic layers correspond in composition, 

 as shown by the interesting analysis in the author's paper, to 

 beds of altered marl ; their density has enabled them to resist 

 and escape, in the present surviving layers, the biotitic altera- 

 tion which has affected the general series. 



In the discussion of the third paper Professor H. F. Osborn 

 remarked on the uncertainty of the age of dinosaur-beds, whether 

 Jurassic or Lower Cretaceous. All determinations hitherto 

 have been made by collectors, but neglected by the palseontol- 

 ogists, though the section is here continuous from the Mountain 

 Limestone of the Carboniferous up to the base of the Creta- 

 ceous. Nor has the correlation yet been made with the corre- 

 sponding beds of the Wealden, Purbeck, etc., of England and 

 the European continent. The aeolian theory of the author, 

 however, does not appear consistent with the reported observa- 

 tions of remains of fish in these beds. 



The chairman, Professor Stevenson, stated that no true 

 Limestone fossils have yet been detected in the bed so called in 

 Wyoming, nor the good evidences yet needed of Jurassic life in 

 the Dinosaur- beds, of other vertebrate life, lacustrine remains. 



