1881 .] 
251 
[Wadsworth. 
strengthened. As it is, the writer fails, except in some cases, to 
see wherein Professor Zirkel’s work is anything more than a sim- 
ple description of the microscopic characters of a series of rocks 
classified by Mr. King. 
Occasion arose in 1879 for the publication of the results of my 
study of the collection under my charge, and in connection with 
it, it also became necessary to give briefly the reasons why the 
results of the Fortieth Parallel work could not be accepted by me, 
A minor portion only of the abstract was devoted to the work of 
Messrs. Zirkel and King. It was then hoped , not promised , that 
within a year the work upon the Sierra Nevada rocks would be 
ready for publication. But my time, since the publication of the 
abstract, has been largely absorbed in other duties, while the 
material to be studied has greatly increased and the plan of the 
work been entirely changed. Mr. Merrill was informed by me as 
to the reason of the delay at the time of his visit to the Museum 
of Comparative Zoology, and he seems to have overlooked the fact 
that the publication of the results of the F ortieth Parallel Explor- 
ation was delayed seven years beyond the time it was originally 
promised. 
At no time has the contemplated publication been abandoned ; 
but heretofore it would not have been proper to publish the 
material contained in the present paper, independently of my 
completed work. 
In what is said in this paper no personal reflections are intended 
to be cast upon those whose work is criticised ; but it is intended 
to criticise the methods, the accuracy of the statements made, 
and the manner in which it has been sought to substantiate the 
work. 
If now the report of Professor Zirkel, together with those of 
Mr. King and his assistants, be examined, one of the first things 
observed is “ the fine silvery-white, scaly mica-slate ” which “ bears 
such a striking resemblance to the well-known beautiful paragon- 
ite slate from Monte Campione, near Faido, at the St. Gotthard, 
Switzerland, that it is difficult to distinguish one from the other, 
— the more so since it contains excellent large crystals of pale- 
blue disthene (cyanite),” (YI, p. 28). Of this Messrs. Emmons and 
