KANSAS ACADEMY OF SCIENCE. 21 



creek, in Davis county, is possessed of such a quantity of calcareous matter 

 that it produces petrifactions of leaves and twigs in a few weeks or months. 



The collectors of the curiosities will frequently tell you that the specimen 

 you are examining is Cottonwood, hickory, or sycamore wood. Some of them 

 may be so, having been made by the more modern agencies referred to. But 

 sometimes we pick up a piece that we call palm wood. This occurs most fre- 

 quently on the western plains as far as Denver. We know that the palm has 

 been petrified by no recent action. It has not grown here since the glacial 

 epoch. Some of the larger specimens that are not palm are also as certainly 

 not recent, but the geologic age to which they belong seems doubtful. We 

 have a few facts that help to assign them to their true period. 



The great advance that has been made in fossil botany through the dis- 

 covery of numerous leaves in the rocks of the Dakota group and the lignitic 

 series, has been as much through the labors of Professor Lesquereux as of 

 any other man, or perhaps any two men; and yet in a communication from 

 him, received by the writer during the past summer, the distinguished pro- 

 fessor says he has no means of identifying fossil wood. Let us remember 

 that the leaves and fruits we have plucked from Dakota forests are not 

 associated with the trunks that bore them aloft in air, hence our ignorance 

 of the structure of the various species of wood that must have existed. But 

 it may be that we are on the confines of positive knowledge on the subject. 

 The writer has in his possession a slab of sandstone from Ottawa county, 

 which, besides other forms, has on it two leaves (not perfect, but very large) 

 of sassafras mirabile, connected and separated by parts which are manifestly 

 the remains of the twig or twigs on which the leaves grew. This stone, sub- 

 jected to the examination of a compent histologist, would give us the structure 

 of this Cretaceous sassafras in its woody fiber. 



On the noi*th line of Dickinson county, in a broad ravine, is a bluiF of 

 stratified sand almost solidified into stone, which has a tertiary facies, but 

 which is overlaid by the fiery-looking ironstones of the Dakota. Out of 

 this bluff, which has been worked as a sand quarry, some time ago there 

 projected the base of the trunk of a tree, about two feet in diameter. Col- 

 lectors have carried it away in parts, gradually digging into the face of the 

 bluff, till there is now a horizontal excavation of about fifteen feet, and yet 

 the top of the trunk has not been reached. The writer has portions of the 

 wood and bark that show a diameter of about eighteen inches, from twelve 

 feet in the cave. If this excavation is carried forward, branches and twigs 

 may be reached, and if a leaf or carpel should be attached, we should have 

 something from which to determine accurately at least one kind of Dakota 

 wood. If such Dakota wood was petrified in more durable forms, it would not 

 be improbable that in the localities of great denudation some of the harder 

 specimens should survive the friction of ages. Some of the specimens of 

 fossil wood we have seen, we are inclined to believe, are from the Dakota, 

 though they are found on the high prairie, far away from the present Cre- 



