G14 E. M. KIXDLE CANADIAN PLEIST0C'E:NE CONCRETIONS 



tive age of the inclosing rock^ divides them into three classes — contem- 

 poraneous, peneconieniporaneous, and subseciuent. 



The concretions described in this paper all belong to the class called 

 ^'^epigenetic" by Tarr — the "subsequent" concretions of Eichardson. 



Labeador Concretions 



The Labrador Pleistocene beds exposed in the Lake Melville district, 

 in the eastern part of the Labrador peninsula, may be divided into three 

 horizons. The base of the series consists of laminated fine-textured 

 marine clays containing at many points an abundant marine fauna. 

 These are followed by beds of similar appearance, but with more perfect 

 and conspicuous lamination, which are nearly, if not quite, barren of 

 fossils. The uppermost beds of this series are Pleistocene sands. 



Small concretions occur sparingly in the beautifully laminated clays 

 which represent the upper portion of the Pleistocene clay beds. These 

 concretions were noted at a single locality only on the Eed Eiver about 

 25 miles northeast of Grand Lake. Here they are of a pale chocolate 

 color and show no considerable variety of form. These concretions are 

 without the organic nuclei so commonly found in the concretions of the 

 lower clays of the Lake Melville basin. Their chocolate-brown color also 

 distinguishes them from the concretions in the older clays. 



Concretions were found at a number of localities in the lower clays. 

 Their general appearance is indicated by the illustrations, plates 5 and (5. 

 The principal loca'lities from which concretions were collected in the 

 Lake Melville district are the clays at the lower end of the Muskrat 

 portage, on the Hamilton Eiver ; a point on tlie south bank of the Hamil- 

 ton about 1 miles below the Muskrat Falls; the l)anks of tlie Kenemicli 

 Eiver; and the exposure of the clays west of Long Point, on the south 

 shore of Lake Melville. Slightly different horizons are probably repre- 

 sented in these different localities. These localities afford a large variety 

 of forms, some of which are shown in the illustrations on plate 5. The 

 concretions from the Muskrat Eapids locality are mostly of a subsplierical 

 symmetrical type (plate 6, figure 3). At another locality 7 miles below 

 Muskrat Eapids the concretions are all of an elongated type, some of 

 them roughly resembling slightly flattened cylinders, others of rib-like 

 shape with rounded ends; these and many other ])eculiar elongate shapes 

 are found here (plate 5, figures 5-<S). 



Sharp contrasts between the composition of the outer shell and tlie 

 interior portion is one of the characteristics Avorthy of note in the Lab- 

 rador concretions fnmi certain localities. The elontrate forms found on 



