TWENTT-FIBST ANNUAL MEETING. 35 



server it would seem that our modern forest leaves are absolutely identical with the 

 cretaceous leaves, which, according to Dana's time ratios, flourished about five mil- 

 lion years ago. The opponents of the modern theory of origin of species by descent 

 have derived a strong argument from the apparent identity of the modern with the 

 ancient forms. But the identity is apparent only; not real. Lesquereux has noted 

 the fact that the Dakota leaves, as a rule, have entire borders, while the modern forms 

 of the same genera have denticulated or serrated borders. Another difference be- 

 tween the modern and the Dakota leaves consists in the greater thickness and tough- 

 ness, or, in botanical language, the coriaceous character of the ancient forms. But 

 in the stipules of the Dakota leaves, we not only have a prevailing unilateral position 

 of these organs, as distinguished from their modern bilateral arrangement, but we 

 are able to witness the gradual change from the single undivided form through the 

 successive steps of transformation to the completely separated and finally bilateral 

 pair; each stage of differentiation being indelibly stereotyped upon the sandstone 

 matrix by which the leaves are enveloped. 



The accompanying plate will show the chief stages in the development of these 

 organs. 



EXPLANATION OF PLATE. 



Figure 1. Betulites Vestii, Lesqx., var. Obtusa, Lesqx., showing unilateral stipule. 



Fig. 2. Betulites Vestii, Lesqx., var. Insequilateralis, Lesqx., showing another form of unilateral 

 stipule. 



Fig. 3. Viburnum Dakotense, Lesqx., var. Longifolia, Lesqx., showing unilateral stipule. 



Fig. 4. Viburnum Dakotense, Les(ix., var. Ovatifolia, Lesqx., showing a narrower unilateral stipule. 



Fig. 5. A detached unilateral stipule and part of petiole, showing the groove in the stipule. 



Fig. 6. Betulites Vestii, Lesqx., var. Latifolia, Lesqx., showing bifurcated unilateral stipule. 



Fig. 7. Detached bifurcated unilateral stipule, showing the base of the petiole. 



Fig. 7a. Opposite side of 7, the stipule itself showing the groove on which the line of division takes 

 place. 



Fig. 8. Betulites Vestii, Lesqx., var. Subintegrifolia, Lesqx., showing bilateral stipules, or the bifur- 

 cated unilateral stipule completely divided and arranged on both sides of the petiole. 



LECTURE.— THE GEOLOGY OF KANSAS. 



[The second night of the session was occupied by a lecture on "The Geology of Kansas," by Prof. 

 K. Hay, Junction City. This was given in the auditorium of the High School. It was illustrated by 

 geological sections, a map, and many specimens. The following is a brief abstract of the address;] 



"Something has been known of the geology of Kansas from the date of the 

 earliest settlement. In the years 1855-8 there was a controversy as to who had the 

 honor of first saying that certain formations were of Permian age. The Carbonif- 

 erous age of rocks in eastern Kansas had already been recognized." 



The lecturer then gave some account of his own work, and the methods of geo- 

 logical investigation, and the relation of the geology to the topography of the State; 

 and then came a succinct account of the succession of formations, from the lowest 

 (in Kansas), the Sub-Carboniferous of the southeast, to the tertiary of the west, and 

 the quaternary deposits of large areas in all parts of the State. The use of the term 

 Permo-Carboniferous was explained and vindicated; and the erosive unconformily of 

 the lowest Cretaceous (Dacotah) on the Permo-Carboniferous in middle-northern 

 Kansas was clearly described; and then followed an account of the position of the 

 Triassic rocks and salt-beds of the southern part of the State. This is a new thing 

 in the geology of the State, and of it the lecturer said, after an illustration of the 

 above-named erosive unconformity: 



"This, on comparison with other parts of our country and Europe, shows an 



