4 SCIENCE PROGRESS. 



red and green shales and interbedded limestones generally 

 siliceous, containing no fossils ; their exact age is therefore 

 as yet unknown. 



2. Cambro-Silurian. Shenandoah Limestone, 4000 

 feet thick, generally a grey dolomite much folded and 

 crushed, at the top are a few feet of blue sparingly fossil- 

 iferous limestone, probably the only representatives of the 

 Trenton-Chazy limestones in this region. The limestones 

 contain conglomerates with pebbles similar in character 

 to the matrix. With reference to the nature of this con- 

 glomerate, the writer states that "its meaning is obscure". 



3. Silurian. Sevier (Hudson River Shale) contains 

 fossiliferous limestones. It is not quite clear why this 

 formation is placed by the writer in the Silurian, if he uses 

 the term " Cambro-Silurian ' in the sense of Ordovician. 

 It is succeeded by the Church (Medina-Oneida) sandstone, 

 the fossiliferous Rockwood (Clinton) formation, and the 

 Giles (Lower Helderberg and Oriskany) formation (the 

 Oriskany and all save the lowest subdivision of the Lower 

 Helderberg are usually included in the Devonian). 



4. Devojiian. Walker Black Shale and Kimberley 

 Shale. 



5. Carboniferous. Price (Pocono) Sandstone closely 

 resembles the upper Coal Measures of the Appalachian 

 basin and is succeeded by the Pulaski shale. 



The author describes five periods of Appalachian fold- 

 ing, the first being in Lower Cambrian times, the second 

 near the top of the Shenandoah limestone, the third which 

 was the main period of deformation occurring between the 

 Devonian and Silurian periods, the fourth near the middle 

 of the Carboniferous, and the fifth, post-Carboniferous. 

 The last has been generally considered the most important 

 of the Appalachian foldings, though " it now seems as 

 though this was no more important than many which 

 preceded it, and that in fact the deformation has been 

 practically continuous since early Palaeozoic time ". 



The second paper to which allusion has been made is on 

 " Palaeozoic Intra-formational Conglomerates" (4). In this 

 various palaeozoic conglomerates are described, with pebbles 



