Diller.] 360 [January 21, 
There are a few observers in this country, and some of them are 
eminent scientists, who contrary to the general belief of lithologists, 
are of the opinion that the felsites of this region are of sedimentary 
origin. To support their hypothesis they depend chiefly upon the 
following arguments. They say: — 
(1) That there is some “ felsite which is clearly interstratified. with 
quarzite, hornblende slate, etc.,” and properly belongs to the strati- 
fied group. To distinguish the felsite of the stratified group from 
that which is not clearly stratified Mr. Crosby calls it stratified felsite. 
(2) That the (unstratified) felsite passes into the stratified felsite 
and “the transition is so gradual that it is impossible to define the 
boundary between ”’ them; 
(8) That the ‘‘ banding ’’ in some of the so-called banded felsites 
‘represents the original bedding of the rock”; 
(4) That on Marblehead Neck and at other places “‘ conglomerate 
and sandstone pass into compact felsite.” 
With reference to the first argument I have already stated (ante p. 
357) that there is no true felsite belonging to the stratified group. A 
microscopic examination shows that the rocks of that group are 
wholly distinct from the felsites both in structure and origin. The 
marked difference between the rocks of the stratified group and the 
felsites I shall point out in detail at some future time. 
The second argument has been most frequently stated and the 
‘« statement ” has been accepted generally as proving that the felsites 
were originally stratified rocks. The felsites and the stratified group 
are associated in Melrose and Saugus. According to Mr. Crosby this 
is not the only area in which such assocation occurs. It is, however, 
the one to which reference is usually made in speaking of the gradual 
transition from felsite to undoubtedly stratified rocks. Much time 
has been spent tracing the boundary between these two groups of 
rocks in order to determine their true relations. 
Near the corner of Washington and Ravine streets in Melrose, 
where the felsite and stratified group are exposed within several 
hundred feet of each other, the two rocks are distinctly different and 
show no signs of gradual passage from-one into the other. The dis- 
tance between the two exposures is about eight hundred and fifty feet, 
and some persons may claim that beds of transition may possibly occur, 
and not be exposed. ‘There is nothing in the two exposures that 
suggests the presence of beds of transition between them,: and 
judging from what may be seen in other localities, I am led to believe 
