348 



SCIENCE 



[N. S. Vol. XXVIII. No. 715 



glomerate, so that we are able to parallel the 

 eastern and western series with certainty. 



The Mesontarie thus becomes a unit of re- 

 markable symmetry. It may be likened to a 

 parabola, which, springing from the marine 

 fauna of the Guelph dolomite, ascends through 

 one Eurypterid fauna (the Pittsford-Shawan- 

 gunk) to a culmination centrally in the 

 barren salt beds (Syracuse) and descends 

 through a second Eurypterid fauna (the 

 Bertie) to a return of marine conditions with 

 Ealysites and other Niagaran types in the 

 Cobleskill dolomite, itself lithologically not 

 unlike the Guelph. 



Unpublished studies by the writer on the 

 Port Ewen fauna have shown its many 

 affinities with that of the overlying Oriskany 

 limestones as known at Glenerie and Becraft's 

 Mountain. Dr. Clarke has, therefore, recom- 

 mended the transfer of these beds to the 

 Oriskanian, in spite of the preponderance of 

 Helderbergian elements. The oft-mooted per- 

 tinence of the Esopus to the Oriskanian also 

 appears to be affirmatively settled, at least for 

 its lower portion, by the writer's finding of 

 Oriskany fossils {Leptocmlia flahellites, 

 Chonostrophia, etc.) forty feet above its base 

 near Leeds, Greene Co. Taonurus cauda- 

 gaUi occurs in the Oriskany limestones at 

 Glenerie. 



In the Rondout region the last-mentioned 

 beds, which may now be formally christened 

 as the Glenerie limestone, are underlaid by 

 eighteen or twenty feet of pebble-beds, typi- 

 cally exposed on the hill above South Eondout 

 (Connelly post-office) and in the creek bank 

 opposite, for which the name Connelly con- 

 glomerate is proposed. Southwestward, as at 

 Cottekill, this latter appears to give way to 

 shaly limestones exactly resembling those of 

 ■the underlying Port Ewen, but having a 

 strongly Oriskany fauna, and it is suspected 

 that these are the equivalent of Barrett's 

 Dalmanites deniatus zone, herein designated 

 provisionally by the name Port Jer^is. 



The new name Kalkberg limestone is pro- 

 posed to cover certain layers heretofore in- 

 cluded variously by writers with the beds 

 above or below (New Scotland and Coeymans) 



and carrying a mixed fauna, highly developed 

 and excellently silicified on Catskill Creek. 

 Here the beds show numerous thin parallel 

 seams of black flint nodules; below these are 

 fourteen feet of typical Coeymans, without 

 flint, and above them are the typically shaly 

 layers of the New Scotland. A similar as- 

 sociation has been found at the Indian 

 Ladder and elsewhere. The fauna is one of 

 the most interesting and abundant in the 

 region and combines Sieberella galeata with 

 Bilolites, Nucleospira, DeltJiyris, Dalmanella, 

 Ehipidomella, Rhynchospira, etc. The name 

 Kalkberg (lime hill) is the local Dutch 

 designation for the Helderbergian ridge, and 

 is pronounced CoUak-barrakh. 



George H. Chadwick 

 St. Laweence Universitt, 

 Canton, N. Y. 



observations upon a yellows disease op the 

 fall dandelion 



The fall dandelion, Leontodon autumnale 

 Linn., is becoming one of the worst of the in- 

 troduced weeds of certain sections of Maine, 

 in meadows, along roadsides and in lawns. 

 This is particularly the case on the lawns of 

 the University of Maine, where the bright 

 yellow flowers are very conspicuous from Au- 

 gust till late autumn, in spite of frequent 

 mowing. 



Here the plant is affected with a " yellows " 

 disease which the writer has had opportunity 

 to observe for the past two seasons. The 

 diseased plants are very characteristic and 

 conspicuous because the foliage becomes much 

 lighter colored and yellowed and tends to 

 grow upward into a rather compact mass, 

 especially if not cut back by the lawn mower. 

 The plant reacts to the stimulus of the dis- 

 ease by producing an abnormal number of 

 leaves and flower heads, particularly the latter. 

 As a rule the scapes are considerably shortened 

 and the flowers abortive, but plants only 

 slightly affected are occasionally observed to 

 form seeds. 



These weeds were very plentiful on the 

 lawns in the fall of 1906 and from 30 per cent, 

 to 50 per cent, of the plants were diseased. 



