Bell — Formations of Horton-Windsor District. 153 



Aet. X. — The Mississippian Formations of the Horton- 

 Windsor District, Nova Scotia; by Walter A. Bell. 



Introductiox. 



The paleontological writings of Sir William Dawson 

 early determined the Horton-Windsor district as the type 

 area for two Mississippian series of formations, the Hor- 

 ton and the Windsor. Later controversies that arose be- 

 tween paleontologists on the one hand, and structural 

 stratigraphers on the other, involved the correlation of 

 the older or Horton formation, a circumstance that lends 

 additional interest to the Mississippian stratigraphy of 

 this district. 



Previous ivorh. — Among the previous workers who 

 have written on the geology are such famous names as Sir 

 William Logan, Sir Charles Lyell, and Sir J. W. Dawson. 

 Logan visited the area in 1841, fresh from his geological 

 studies in South Wales, where he had so ably established 

 the true nature of Stigmarian underclays. His discovery 

 in the Horton formation of amphibian footprints {Sy- 

 lopus logani Dawson), in conjunction with the coal-meas- 

 ure appearance of the Horton strata and of the contained 

 flora, led him to consider these beds of Coal Measures age. 

 The gypsiferous or Windsor series was recognized as 

 stratigraphically younger, and fossils gathered at Wind- 

 sor and submitted to De Verneuil, Keyserling, and Mur- 

 chison were first regarded as Permian in age. This 

 correlation, however, was doubted by Sir Charles Lyell as 

 long ago as 1843, and he was the first to assign both the 

 Windsor and Horton beds to the lower Carboniferous, a 

 conclusion soon corroborated by Sir William Dawson. 

 For the next fifty years Dawson contributed various 

 papers dealing with the flora, fauna, and stratigraphical 

 relations of these Mississippian rocks. His observations 

 and conclusions are admirably presented in the various 

 editions of his ^^ Acadian Geology.'' 



Later references to the correlation of the Mississippian 

 formations are made by David Wliite, R. Kidston, A. 

 Smith Woodward, L. M. Lambe, H. M. Ami, Charles 

 Schuchert, and J. W. Beede. Wliite (1901) assigned the 

 Horton a Kinderhookian age, with a partial equivalence 



^Published by permission of the Director of the Geological Survey of 

 Canada. 



