720 GEOLOGY OF OLD HAMPSHIEE COUNTY, MASS. 



midrib, which I found to be the case also in the dried specimens studied. 

 Small sessile seed vessels, several on one stalk, also occur in several cases. 

 Hadley, and Hampshire Park, Amherst. 



Lycopodium selago L. — I have referred to this species a single specimen 

 agreeing with it in habit and in shape of leaf, but much smaller. Hamp- 

 shire Park, Amherst. 



In 1835 Dr. Hitchcock described fossils from Deei'field, Greenfield, and 

 South Hadley, of a single genus in an imperfect state, resembling Ovulites 

 margantula Goldfuss or Scyphia, which the full description shows to have 

 been feiTUginous pipe.stem concretions.^ 



BUKROWS OF DIPTEROUS LARViE. 



Over many surfaces of the laminse Avhich were free from the delicate 

 rippling I have described above (p. 703), and were exceptionally smooth 

 and fine-grained, run delicate raised threads in regular undulations, each 

 curve being 4™" long and 3'™ deep. At times the raised tlu-ead is replaced 

 by a groove of corres})onding size, 1 to 1^"" in width. These may have 

 been formed by minute worms burrowing just below the surface and raising 

 a ridge, which sometimes sank, in to form the corresponding groove. They 

 occur 30 to 40""" in length. It is also interesting that the claystones have 

 taken the cast of the partings between the clay layers so accurately that in 

 the large disk-shaped stone figured in PI. XX, p. 716, both sides are covered 

 by the grooves and ridges, and these show distinctly in the photograph. 

 The claystone came from a point 30 feet below the level of the Connecticut 

 at the west pier of the railroad bridge. The same trails appear abundantly 

 on the surface of the folded claystone figured on the same plate; the exact 

 locality" from which this stone came is not known, but it is probably in 

 Northampton or Hatfield. These tracks were first figured by Htigbom^ 

 from interglacial clays in Jemtland, Sweden. They were later described 

 by Dr. Gunnar Anderson^ from Jemtland and Finland. They were iden- 

 tified by him w^ith the traces made by the larva of the dipterous insect 

 Chironomus motUator. 



These traces have been found from the strandzone to 300 fathoms in 

 depth, in salt and fresh water, and in both temperate and arctic climates.* 



' Geology of Massacliusetts, p. 182. 



-Geol. Foreningens Stockholm Fijrhandl., Vol. XV, 1893, p. 29. 

 ' Sveriges Geol. Undersokning, Series C, No. 166, 1897, p. 22 (60). 



*Fr. Meinert, De eucephale Myggelarver: Kjiibenliavn. Videusk. Selsk. Skiifter, 6 Raekke, Vol. 

 Ill, 4, 1886, pp. .141-441. 



