M.viicii 3, 1005.] 



SCIENCE. 



349 



logical Society are reported. The ' Periscope ' 

 includes abstracts of the following period- 

 icals: Neurolog inches Centralhlatt, Journal de 

 Neurologie, Allgemeine Zeitschrift fiir Psij- 

 chiatrie. Journal of Mental Science, Archives 

 de Neurologie, and selected articles from 

 miscellaneous journals. T. S. Clouston's 

 * Clinical Lectures on Mental Diseases ' and 

 ' Traitc de Medicine,' Vol. IX., Diseases of 

 the Nervous System, are reviewed. 



SOCIETIES AND ACADEMIES. 



THE CJEOLOGICAL SOCIETY OF WASHIXGTOX. 



Tlie Bed Beds of Soidhivestern Colorado: 



Whitman Cross and Ernest Howe. 



During the areal mapping of the Ouray 

 quadrangle, on the north side of the San Juan 

 Mountains last season, a notable angular un- 

 conformity was observed immediately below a 

 peculiar limestone conglomerate which has 

 long been known to carry fragmentary re- 

 mains of dinosaurs and crocodiles, with occa- 

 sional plant and invertebrate forms, all of 

 Triassic types (see Telluride and La Plata 

 folios). Within a distance of two or three 

 miles this Triassic conglomerate is seen to 

 transgress the edges of 1,200 feet or more of 

 imfossiliferous conglomerates, sandstones and 

 shales, of typical Eed Bed character, and sev- 

 eral hundred feet of the TTermosa formation — 

 Peunsjdvanian Carboniferous. The Triassic 

 beds are here but 50 to 200 feet thick, the La 

 Plata Jurassic sand-stone resting unconform- 

 ably upon them. 



This unconformity below the Trias shows 

 that the major portion of the Red Beds section 

 of the San Juan country is Paleozoic and the 

 authors provisionally refer that portion to the 

 Permian, and propose the name Cutler For- 

 mation for it, the Triassic Red Beds retaining 

 the nasne Dolores, in accordance with the 

 original definition of that formation. 



The significance of th!s unconformity in 

 intei-preting the Red Beds sections of other 

 parts of Colorado and the western plateau 

 country was briefly discussed. This paper 

 was read by title at the winter meeting of the 

 Geological Society of America and will be 

 offered for publication in full in the Bulletin. 



Cause and Periods of Earthquakes in the New 

 Madrid Area, Missouri and Arkansas: 

 Myron L. Fuller. 



The term New Madrid earthquake is ap- 

 plied to a series of shocks beginning late in 

 1811 and continuing to the early part of 1813, 

 constituting one of the most remarkable ex- 

 amples of incessant quaking in a region far 

 from any volcano for a period of many months. 

 The shocks, though felt throughout nearly 

 the whole of the country then settled, were 

 most severe in southeastern Missouri, north- 

 eastern Arkansas and western Tennessee. 

 Along the Mississippi there is said to have 

 been a broad dome-like uplift of some twenty 

 feet, while both to the east and west the land 

 was depressed, forming the broad ' sunk land ' 

 districts. The uplift resulted in the drainage 

 of many lakes and bayous, while the depres- 

 sion gave rise to basins into which waters 

 flowed, killing the existing timber. Among 

 other characteristic features of the earth- 

 quake was the opening of immense cracks, 

 often several feet across and many feet in 

 depth, and the formation of craterlets, through 

 both of which large amounts of lignite-bear- 

 ing sands were ejected, probably giving rise 

 to the broad areas known as sand-slews where 

 the surface, even to-day, is in places a barren, 

 sandy, timberless waste, upon which only 

 weeds will grow. The submerged stumps, 

 slews, craterlets and cracks were still visible 

 in 1904 when a trip was made to the region by 

 Professor E. M. Shepard, C. B. Bailey and 

 the speaker. Professor Shepard, who gave 

 much attention to the cause of the earthquake, 

 believes that the conditions are such as 

 woiald result from the undermining action of 

 ground waters under artesian pressure and 

 which are thought to have escaped in the 

 past, as possibly at present, along some of the 

 streams by springs bringing up sand and 

 lignite. The equilibrium being destroyed by 

 a readjustment of some Ozark or other fault, 

 cracks were formed and sand and water 

 ejected in large amounts, permitting the set- 

 tling described. The speaker, however, be- 

 lieves that there was no preliminary under- 

 mining, but that the sinlcing was brought about 

 because of the extrusion at the time of the 



