[Assembly, No. 104.] 227 



ing upon the subject of ihe distribution of the economic products of 

 the State, such as the marbles, granites, iron ores, etc. The collections 

 made in this investigation are enumerated under the head of additions 

 to the Geological department of the Museum. The results will be com- 

 municated to the Museum report for publication and will be regarded 

 only as preliminary to further and continued investigation. 



At my request, 'Mr. C. E. Beecher and Mr. (J. E. Hall have made 

 some special investigations along the Mohawk valley from Little Falls 

 to Schenectady, with a view to some determinations regarding the 

 junction of the Upper Laurentian gneiss with the superincumbent 

 rocks, and also to make some determinations regarding the faulting of 

 the strata, first noticed by Mr. Vanuxem more than forty years ago. 

 The localities of contact are very few, and the single one formerly 

 known on the old stage road at the Noses has long since become ob- 

 scured. 



At Little Falls the gneiss is succeeded by massive Calciferous sand- 

 stone, but notwithstanding the excavations in quarrying, and finally 

 for the West Shore railroad, no actual contacts of the rocks of the 

 two systems have been exposed. 



In digging a well through the lower beds of the Calciferous sand- 

 stone into the gneiss, a stratum of ferruginous sand was penetrated, 

 lying in contact with the gneiss, below and separated from the Calcif- 

 erous above. This locality was examined by myself in 1881; and it 

 having come to our knowledge that the cutting of the West Shore rail- 

 road at the Little Nose exposed similar strata, the place was visited 

 by Mr. McGee of the United States Geological Survey, and myself, in 

 the autumn of 188-4, and observations made upon the contacts there 

 exposed. 



An examination was also made of the Oneonta sandstone in the 

 vicinity of Oxford, Chenango county, by Mr. C. E. Beecher, Dr. J. W. 

 Hall and C. E. Hall. Much discussion has recently taken place in 

 regard to the horizon and equivalency of the Oneonta sandstone. The 

 results of the more recent investigations haye served to substantiate my 

 previous published statements, and clearly show that the Oneonta sand- 

 stone rests upon well marked Hamilton strata, and is succeeded by strata 

 carrying the fossils of the Chemung Group. 



The draughtsmen now employed upon the palsontological work are 

 Mr. George B. Simpson and Mr. Ebenezer Emmons. At the present 

 time all the work is done by the figure; the price paid being at the 

 uniform rate of 83.50 per figure. 



JAMES HALL, 



State Geologist. 



Paleontology of New Yoek, vol. V, p. II, Lamellibranchiata, ii 



Table of Contexts. Page. 



D EDiCATioN iii-iv 



Table of Contents v-vi 



Preface vii-x 



Introduction xi-xxii 



Synopsis of the Genera xxiii-lxii 



