FOUND IN CANADIAN ROCKS WESTON. 3 



similar concretions in a Cretaceous rock of Grand Rapids, Atha- 

 basca River*, as follows : 



" It is remarkable for the large number of spheroidal siliceous 

 concretions which it contains, and which range in size up to ten 

 feet or more in diameter. No fossils were found in the concre- 

 tions or in the rocks which hold them." 



The same agency which produced these great concretions no 

 doubt formed the smaller pipe-stem concretions, so numerous 

 in the Miocene rocks at the head waters of Swift Current, N. 

 W. T., and which are now being formed on the shores of Lake 

 Cham plain. 



4. Another interesting concretion locality lies half a mile west 

 of White Mud River, near the Fort Walsh trail, in the Assini- 

 boine district, N. W. T., the rocks belonging to the Laramie 

 formation. Here a small butte was pointed out to me by my 

 half-breed Indian guide, who called the place gun-shot butte, 

 and said a few years ago when he, with others, hunted buffalo 

 in that locality, they sometimes, when ammunition was scarce, 

 used these " balls " in their guns and rifles. I found the hill, or 

 butte, to consist largely of calcareous sand, which contained 

 enormous quantities of spheroidal concretions, varying in size 

 from that of buck-shot to an inch in diameter ; the ordinary 

 size being that of rifle balls. A great number of these are 

 compound forms representing two halves of a sphere coalescing 

 together, sometimes a number of these marbles (as the Indians 

 call them), are clustered together into pieces as large as one's 

 head. They are all more or less covered with nodes. About 

 one-third of each is carbonate of lime, which dissolves out with 

 muriatic acid, leaving a residue (as seen under the microscope), 

 of grains of pure silex, with a few of feldspar, magnetite, and 

 mica. There are no concentric layers and no nuclei. 



5. The Animikie argentiferous rocks of the Thunder Bay dis- 

 trict are remarkable for " bombs," so called by the miners. At the 

 Beaver silver mine, a few miles from Port Arthur, many concre- 

 tions resembling cannon balls may be seen in the black 

 carbonaceous. slates which are largely developed at this locality. 



* Geological Survey Report for 1889-90-91. 



