42 THE LEWIS BROOKS MUSEUM. 



raised the Appalachian coal field high in the air, took place 

 in the Permian. 



The greater expanse of land, its greater diversity of 

 altitude, the brighter sun and purer air made themselves 

 felt in the vegetation of the next following Mesozoic time, 

 and go on increasing in effect all through it. In accordance 

 with the general law, some of the Mesozoic plants made 

 their first appearance in the Permian. Among them we 

 find coniferous trees, preferring hilly grounds, like the mo- 

 dern pines, and sun-loving plants, such as the cycads and 

 zamias, many forms of which still live in tropical and 

 sub tropical lands. The peculiar type of conifer, now rep- 

 resented by the single species, gingko or salisburia, made 

 its first appearance in the last stages of the Carboniferous 

 age. The Permo-Carboniferous beds of West Virginia 

 yield a form so close to the modern salisburia that Count 

 Saporta affirms that it is a true salisburia. The cycads, 

 zamias and gingkos are greatly developed in the Mesozoic, 

 attaining their culmination about the middle of the time. 

 They are compound types, and with ferns, conifers and the 

 equisitae, make up almost entirely the vegetation of this 

 time. The equisitae are not essentially different from the 

 living ones, and with some of the ferns establish a closer re- 

 lation with the present vegetation. There is in the vegeta- 

 tion of the Mesozoic a marked progression towards modern 

 characters. But still, when compared with our present 

 plants, it is more generalized and of lower grade. The 

 types of plants which characterize the Mesozoic reach their 

 culmination in the middle Mesozoic, and end in the lower 

 Cretaceous. Here we find a change of great significance 

 taking place. In the lower Cretaceous occur, so far as is 

 yet positively known, the first angiospermous plants — *. e., 

 forms similar to our modern flowering plants and forest 

 growths. This type of vegetation, having true flowers and 

 seed vessels, now predominates by far on the earth. But in 

 the lower Cretaceous there is, as yet, only a single species 



