310 H. M. AMI — KNOYDART FORMATION OF NOVA SCOTIA 



pared and submitted to Doctor A. E. Barlow, of the Geological Survey of 

 Canada. He kindly undertook to describe these, and gave the follow- 

 ing interesting note regarding the tufaceous or volcanic origin of locality 

 number 6, and number 44 of Mr Hugh Fletcher's section : 



"The rock of McAnas brook is a dark gray to greenish gray thinly bedded gray- 

 wacke, weathering yellowisli or brownish, owing to tlie decomposition of the iron 

 ore. It is composed for the most part of angular, subangular, and rounded grains 

 of quartz and feldspar embedded in a matrix of th^ same materials in a finer state 

 of division. Calcite is present, and in some sections is a rather abundant compo- 

 nent of the groundmass. Chlorite in occasional plates and small scales of sericite 

 is also present. The rock is probably of tufaceous origin. Small seams or veins of 

 calcite and quartz frequently traverse the rock." 



Paleontologic Notes and Faunal Relations 



In reporting upon the fish fauna from this formation, Doctor Smith- 

 Woodward writes : "The Mc Arras Brook specimens represent the base 

 of the Lower Old Red sandstone of Britain." 



The presence of pteraspidians, cephahispidians, and acanthodians, as 

 well as Pterygotus, as determined ))y Mr A. Smith-Woodward and Doctor 

 Henry Woodward, of the British Museum, would seem to indicate clearly 

 the presence of a fauna precisely similar in facies to that of the Hereford 

 beds, refera})le to tlie Lower Devonian (Old Red Sandstone) or Cornstone. 



The Pteraspis found in the tufaceous rock in the series of strata is one 

 which Mr Woodward refers to as very closely allied to, if not actually 

 identical with, P. crouchii of the English rocks. 



The horizon indicated is low down in the Devonian and not far from 

 the summit of the Silurian. From the nature of the sediments, their 

 composition, origin, and general characters they a})pear to be much more 

 closely related to European Devonian or Old Red Sandstone strata than 

 to the usual type of North American Devonian, such as are met with in 

 synchronous western epi-continental formations. 



Sir Archibald Geikie* points out the occurrence in Nova Scotia and 

 New Brunswick of the two divergent Devonian and Old Red Sandstone 

 types of Euroi)e, but does not attempt to give any of 'the subdivisions 

 of the rocks of this system nor any of the fossil organic remains found 

 in them. The fauna of the Arbroath flags or Lower Old Red Sandstone 

 of Murchison is remarkably similar to that of the Knoydart formation. 



In his " Geology, Chemical, Physical, and Stratigraphical," Sir Joseph 

 Prestwich t makes the following statement regarding the " Old Red 



*Text Book of Geology, 189o edition, book vi, part 2, sec. 3, chap. 2, par. 2. p. 803, 

 t Chapter vi, " The Devonian system : ' The Old Red Sandstone,' p. 82." 



