January 18, 1895.] 



SCIENCE. 



65 



the beds, and hence appeaU'd to cliniatio 

 cycles. 



Tlie cycles of a year's changing seasons is 

 too short to account for the limestone ; the 

 next longer cycle, the lunar, involves no 

 changes of climate ; hence the cj^cle of the 

 precession of tlie e(|iiinoxes, 21,000 j'cars 

 long, was selected, and allowing four feet of 

 de}X)sit for each cycle, tliis portion of Cretace- 

 ons time was estimated at 21,000,000 years. 



There was no discussion, but a very cAi- 

 dent feeling of solemnity at the announce- 

 ment. 



33. Notes on the Cretaceous of Weste7-n Tex- 

 as and Coahuila, Mexico. E. T. Dumble, 

 Austin, Texas. 



The author being absent the paper was 

 only read by title. 



The main section then adjourned until 

 the pre.sidental addi-ess at 7:30 the same 

 evening, ileantime the peti-ographers lis- 

 teni'd to 



34. Spheriililic Volcanics at North Haveni 

 Maine. W. S. Bayley, Water^ille, Me. 

 In the Journal of Geologj' a few months 



ago the late Dr. George H.Williams referred 

 to the existence of old rhyolit«s on the 

 coast of ilaine. The author described very 

 briefly the occurrence of these rocks, and 

 exhibited specimens of them. The speci- 

 mens showed very perfect spherulites, litho- 

 physie and all the common features of glassy 

 volcanics. Tliey brought out an interesting 

 discussion regarding the abundance of these 

 rocks along the Altantic sea-board. J. E. 

 Wolft" spoke of theii- great extent near Bos- 

 ton, and especially at Blue ECill, where the 

 relations with the Quincy gi-anite are a hard 

 problem. A. C. Lane mentioned their fre- 

 quency in central Elaine, as shown by the 

 collections of L. L. Hubbard. T. G. White 

 referred to those near Mt. Desert. J. F. 

 Kemp spoke of recent field and peti-ogra- 

 phic work in progress on the gi'cat areas 

 near St. John, N. B. W. S. Ycates brought 

 up the curious phosphatic spherulites lately 



found in Georgia, which closely simulate 

 litliophysjT, and remarks were made on 

 them by W. Cross and J. P. Idtlings. 

 35. The Peripheral I'hases of the Great Gab- 



hro Mai's of Xorthca.4ern Miniie-'<ofa. W. 



S. Baylky, A\'aterville, Me. 



On the northern border of the gi-eat gab- 

 bro mass in nortlieast«m Minnesota are 

 basic and gi-anulitic rocks whose composi- 

 tion indicates tlieir relationships with the 

 gabljros with which they are associated. 

 The basic rocks arc aggregates of the basic 

 constituents of the gabbro. They are char- 

 acterized especially by the abundance of 

 titanic iron. The granulitic rocks dilVer 

 fi-om the central gabbro mainly in struc- 

 ture. They consist of aggi-egates of rounded 

 diallage, hypersthene and plagioclase. all of 

 wliicli minerals are present also in the nor- 

 mal rocks. The Ijasic rocks are probably 

 differentiated phases of the gabbro, of ear- 

 lier age than the great mass of the nor- 

 mal rock. The granulitic phases are simplj- 

 periplieral phases. Closely parallel cases 

 were brought out in the discu.ssion as 

 existing in the AcUrondacks (by C. H. 

 Smyth, Jr., and J. F. Kemp), and in Que- 

 bec (F. D. Adams), where they have been 

 been called granulites, augite-syenites and 

 augite gneisses. H. D. Campbell mentioned 

 the sjime phenomena in similar i-ocks in 

 Rockbridge county, Virginia, and all the 

 speakers commented on the peculiar devel- 

 opment of orthoclase feldspar in the border 

 facies of a gabbro mass. 

 86. The Contact Phenomena at Pigeon Point, 



Minn. W. S. Bayley, Wat*rA-ille, Me. 



The speaker distributed copies of his re- 

 cent Bulletin U. S. Geol. Suiwey, Xo. lO't. 

 and exhibited a series of specimens which 

 illustrate the peculiar contacts and transi- 

 tion rocks at Pigeon Point. Discussion fol- 

 lowed bj' by J. P. hidings and others. 

 37. A Xew Di.->covirij of Peridotife at Deiritt, 



3 miles east of Si/raeiise, N. Y. N. H. Dar- 



TON. Petroyraphij of same, J. F. Kemp. 



