December, 1918] 



The Ottawa Naturalist 



115 



diameter ranging from three-fourths of an inch to 

 two inches. The bedding is somewhat heavier and 

 occasionally the stone bears a trace of ripple mark. 

 The surfaces of the polygons are as a rule nearly 

 flat; the down warp is apparent in only the larger 

 of them. 



The figure shows two specimens of mud-crack 

 from this bed. The smaller (fig. 1, A) is of the 

 first type; the larger (fig. 1,B) of the second. 

 Both are from the same large slab. 



Using the experiments of Dr. E. M. Kindle,* in 

 his study of the formation of mud cracks, as a basis 

 for his deductions the writer concludes that at the 

 beginnmg of the period durmg which these cracks 

 were formed the water was of a higher degree of 

 salinity than that of ordinary sea water. The larger 



cracks of the lower portions of the beds show that 

 at first the process of desication was more rapid than 

 it was during the time when the upper portion of the 

 horizon was laid down. The conditions affecting 

 dessication, however, were not entirely stable for 

 layers immediately above the large specimen figured 

 contain cracks that average a larger size. The con- 

 ditions as a whole, however, were fairly uniform and 

 the changes were gradual. The mud was probably 

 of a marly character. 



It is impossible of course to make a definite 

 statement as to the cause and conditions of forma- 

 tion of this horizon. The sea bottom was evidently 

 raised over a wide area. The change from normal 

 sea bottom to a wide partially submerged flat was 

 of a temporary character. 



NOTES AND OBSERVATIONS. 



Equisetum robustum a. Br. in Ontario. 

 During the month of November, 1918, a specimen 

 of Horsetail was sent in for identification by Mr. F. 

 J. Perkins, Hope Farm, Kingston, Ontario, which 

 proved to be the above species. Mr. Perkins states 

 that he found it in a wooded lot close to his own 

 grounds. 



This species, although known from British Col- 

 umbia, does not appear to have been found else- 

 where in Canada. Dodge's Flora of Point Pelee 

 mentions it as occurring on the small islands near 

 the Ohio shore; it has also been found in the State 

 of New York, which is apparently its northern 

 limit in the east. 



J. Adams, Division of Botany, 

 Exp. Farms, Ottawa. 



Errata. The Genus Vespa in Canada. In 

 the typing of my original manuscript of the article 

 which appeared in the October issue of The OT- 

 TAWA Naturalist, an important couplet relating to 

 the species consohrina was omitted. The following 

 corrections should be made: 



Page 71, column 2, line 11; for "stipes" read 

 "stripes"; line 18, insert "7" before "hairs. 



Page 72, column 1, under "RuFA GroUp" insert 

 the following: "9. Markings white. Male 2068, 

 female 2067, consohrina, Ont. to B.C. Sauss. Mark- 

 ings yellow .... 10." 



Page 72, column 1, line 7, for "9" read "10"; 

 line 23, for "10" read "11"; line 24, for "10" read 



"11"; column 2, line 20, for "11" read "12"; line 

 2 1 , f or " 11 " read " 1 2." F. W. L. Sladen. 



*Some factors affecting the development of mud 

 cracks, Journ. Geol. vol. 25, 1917, pp. 135-144. 



Chipmonks; With Special Reference to 

 Their Indinidual Disposition, Cheek Capacity, 

 and Hanging Ability. We have two chipmonks 

 at our house, chipmonks which were born on the 

 Eraser plateau of the southern interior of British 

 Columbia, and which were caught in a figure four 

 trap, and transported to a prison camp in Ottawa. 

 Not so much a prison camp after all, as when let 

 out they sometimes go back into the cage to store 

 their gleanings of food. At other times they run 

 over or under us, apparently without the slightest 

 fear, rather than be driven towards the cage. They 

 can stuff seven large kernels of corn in their mouths 

 and hold them in their cheeks. 



One of them often watches us, comes to the front 

 of the cage when we approach, eats out of our hand 

 and at times even sits on it when eating. We call 

 him Labor, because he does all the work and loses 

 most of his pay. Some scientists would call him 

 Labor hustleus, variety goodwillie. The other sulks 

 in a corner, never comes to meet us, seldom eats out 

 of our hand, and always attacks Labor as soon as he 

 has any tidbit. He often takes it away from him. 

 We commonly call him Capital, although known 

 to science as Capital greedius, variety auiocratus. 



One morning Labor took a fragment of nut meat 

 from my hand and was fiercely attacked by Capital. 

 He fled to the top of the cage as usual. This is 

 made of wire netting. There he hung by his four 

 feet watching lazy Capital switching his tail in 

 anger, too lazy to pursue him further. Then in 

 order to hold the nut meat with his forepaws, he let 

 go his hold with them and hung free by his hind 



