330 DAWSON \M» PENHALLOW — PLEISTOCENE PLORA. 



the midrib vary considerahly in the same species, so that this cannot be re- 

 garded as a character of more than approximate value. The number and 

 distribution of the veine offers a somewhat more reliable guide, aince there 

 is a constancy in this respect which is of value. The majority of our maples 

 tall in one of two types. In the first case, four principal vein- are arranged 

 palmately with the midrib, and directly extend to as many distinct lobes of 

 the leaf, the first pair usually extending horizontally or obliquely downward 

 to the basal lobes. To this type can he referred such species as Acer ptata- 

 unit!,.* and .1. siici-hnriiniin. In the second case, only two principal vein- are 

 directly and palmately arranged with the midrib, while from each of them 

 there Bprings a subordinate vein at a short distance from the base, which 

 then extends to the corresponding basal lobe. Examples of this type are 

 to he mi n in Acer rubrum and A. dasycarpum, as well as in the fossil A. 

 pleetoa ni nun. 



In the fossil under consideration there are four distinct veins palmately 

 arranged with the midrib, two of which are large, and the other two run- 

 ning to the basal lobes. It will thus he seen that comparison with Acer 

 montanum cannot he considered. A close comparison with the leaves of the 

 first group shows that it approaches most nearly to Acer saccharinum in all 

 those characters represented. 



The present distribution of A. saccharinum covers a wide range through- 

 out Canada, from Newfoundland and Nova Scotia to the western extremity 

 of Lake Superior, and northward to Lake St. John and to the Long portage 

 on the Michipicoten river. 



POTENTILLA ANSKKINA, I.. 



Two specimens and their reverses in nodules previously determined as 

 Potentilla canadensis and /'. norvegica, and also a specimen ami it- re- 

 verse in Mr. Miller's collection in the Peter Redpath Museum. The leaves 

 only are represented, hut the venation is so distinctly preserved, as well as 

 the general form and margin, as to leave little doubt as to their true char- 

 acter, although iii one case tiny are ao grouped by crushing as to hear a cer- 

 tain resemblance to the leaf of P. canadensis. In this Bpecies the veins run 



directly from the midrib of the leaflet to both teeth and sinuse8. In /'. imr- 

 vegica the veins run to the teeth, taking a direction which tends to become 

 parallel with the margin, and while the vein it-elf extends into a tooth it 



off a lateral which penetrates the t"<>th below, SO that there are in 



r< ality twice a- many teeth a- veins. The fossils, which in this respect as in 



other- :ire :d| -imihir. .-how the vein.- running directly to every tooth, veins 



and teeth being equal in number. 



In this respect, a- well as in the form of the leaflet, the shape and apices 



• i , Vol. III. 1868, p. 7". 



