300 New York State Museum 



Literature. For the general discussion of these two 

 systems the textbooks referred to under the preceding- 

 chapter on the Cambrian and Ozarkian may be used. 

 To these references are added Bassler ('19), Grabau 

 ('09), Schuchert ('10, '14) and Ulrich ('11). 



Among- the publications having reference to the New 

 York formations the following are suggested : Brainerd 

 and Seely ('90, '91, '96), Chadwick ('20), Clark ('19), 

 Clarke ('99), Cushing ('05a, '08, '11), dishing, Fair- 

 child, Ruedemann and Smythe ('10), Foerste ('14), 

 Hartnagel ('12), Holzwasser ('26), Miller ('09, '17, '24, 

 with many references), Prosser and Cummings ('97), 

 Raymond ('14), Ruedemann ('01a, b, '02, '03, '05, '06, 

 '08, '10 (in Cushing etc., Bui. 145), '12, '19, '25, '30), 

 Ulrich and Cushing ('10), Ulrich and Schuchert ('01). 



Silurian Period 



The name Silurian was given by Sir Roderick 

 Murchisoi (1835) to a system of rocks occurring be- 

 neath the Old Red Sandstone series (Devonian) and 

 previously unknown. He studied them on the border- 

 land between England and southern Wales where 

 they were least disturbed, and therefore gave to the 

 system a name derived from the Silures, a warlike tribe 

 that occupied this territory in the days of the Romans. 

 "The Silurian System" appeared in 1838. Murchison 

 then divided the system into an upper and lower divi- 

 sion, the latter essentially of the age of Sedgwick's 

 Upper Cambrian of North Wales for which Lapworth 

 subsequently proposed the now generally accepted 

 term Ordovician system. At the same time Lapworth 

 also advocated restriction of the name Silurian to the 



