100 Eepoet of the State Geologist. 



For a description of the fauna of this basal rock the reader is 

 referred to a note kindly furnished by J. M. Clarke."^ No distinc- 

 tion was found between the different localities, in respect to 

 fossils. 



The " Transition shales," of wide distribution in Ontario, 

 Yates and Livingston counties, are faintly indicated in three or 

 four feet of shale at the foot of the Lodi fall, and a little at the 

 top of the bank in Highland creek. At Faucett's they are 

 absent. 



Above this layer there is green sandy shale with a few layers 

 of thin hard sandstone. This material, however, is replaced 

 twice within the first hundred feet, as may be seen in the sec- 

 tions (figs. 26, 27) — first, by 10 feet or more of excessively frail 

 black shale, stained brown by iron, and second, by a 40-foot 

 layer of less fragile black shale quite like the Genesee. Sand- 



* Note.— This irregular concretionary and Impure calcareous stratum which Dr. Lincoln describes as 

 occupj-lng a well-defined position at the top of the Genesee shales carries a fauna of considerable 

 interest. The preservation of the fossils is execrable, and it would be highly difflcult to get any 

 conception of the fauna from an examination of the stratum without artificial helps, but a simple 

 process which I have long used for the elucidation of fossils from just such argillaceous limestone as 

 this, has served to bring out a pretty full illustration of the fauna so far as represented in the 

 material which has come into my hands. It may be of use to others if this process be briefly 

 explained. The given condition is an impure argillaceous or arenaceous limestone with the sub- 

 stance pf the fossils a semicrystalline calcite. To anj' manual process employing tools, the elucida- 

 tion of the fossils in such a matrix would be insolvable. Let small fragments exposing fossils In 

 section be placed in dilute muriatic acid until the calcareous matter is removed to a sufficient depth 

 from the surface to leave all impressions.of fossils at the surface perfectly clear. The argillaceous or 

 other impurity of the matrix left after the reaction will be exceedingly' soft, but retain the 

 Impression, whether external or internal, with exceeding delicacy of detail. The fragments may 

 then be carefully removed from the acid and washed by placing for a moment in pure water. They 

 should then be thoroughly' dried, and afterward h-ardened by cautiously soaking in a very weak 

 solution of glue, care being taken that this solution be sufficiently thin to enter all the ornamental 

 or structural cavities and interstices of the impressions. After again drying, sharp, clean and clear 

 squeezes are to be taken with soft gutta-percha. To preserve the hardened matrix such squeezes 

 must be taken rapidly lest the heat of the gutta-percha soften the glue and cause adhesion. If, how- 

 ever, the destruction of the matrix is not of moment, the gutta-percha may be withdrawn at will 

 and the adhering dirt soaked and washed off at leisure. In my own experience this process has 

 given extremely happy results, detail being reproduced with surprising delicacy. In illustration I 

 may especially quote the calcareous shales of the Hamilton group from which have been obtained 

 many such replicas of well-known species which portray a surface ornamentation in some Instances 

 barely suggested in the published illustrations. The following species have been recognized by the 

 use of this method, in this limestone at Lodi Falls. 



icc= abundant ; c = common ; r = rare.) 



Goniatites Patersoni, Hall, small form • • »* 



G. sp. a small form with sutures like G. sinuosus *' 



Bactrites sp . • o 



Gomphoceras of. manes, Hall »' 



Palceotrochus prcecursor , Clarke • (^ 



Pleurotomaria capillaria. Hall. 



There, are two varieties present of this species, one of which surpasses In size that prevailing In 

 the Hamilton shales, while the other Is considerably smaller. They are quite distinct In aspect 



though not separable from the species. Both are abundant co 



Loxonema Noe, Clarke *^° 



