172 THE ROMAN COMAGMATIC REGION. 
magmas, the spatial relations of the different magmas and types being discussed 
elsewhere, and shall then attempt to estimate the average composition of the 
whole. 
QUANTITATIVE RELATIONS OF THE MAGMAS. 
The persalanes, while widely distributed, are not the most abundant rocks, 
forming possibly but one-quarter or one-third of the whole. The great majority 
belong to the perfelic order canadare, rocks of the lenic orders russare and tas- 
manare being rare. For the most part they are domalkalic, either vulsinose or 
pulaskose, the former subrang being the more abundant, with the peralkalic and 
sodipotassic phlegrose in greater amount than pulaskose but less than vulsinose. 
The dosalanes constitute the greater part of the rocks, one might say rather 
more than one-half. Of these those belonging to the quaric order austrare are 
very few, the perfelic germanares are very abundant, and probably in somewhat 
greater amount than these last are collectively the lenic norgares, italares, and cam- 
panares. By far the most of the rocks which fall in this class are domalkalic, with 
fewer alkalicalcic and no peralkalic or docalcic ones. The subrangs are generally 
dopotassic, though sodipotassic subrangs are not unusual, but are generally con- 
fined to the less common types. Of the subrangs of dosalane it may be said that 
ciminose, braccianose, and vicose are most abundant, with less amounts of mon- 
zonose and vesuvose, the others being comparatively rare. 
The salfemanes are less abundantly represented than either of the other two 
classes, and probably considerably less than a quarter, let us say one-fifth, of the 
rocks belong here. With few exceptions the salfemane rocks are in the lendofelic 
order of bohemare, and of the subrangs of salfemane that of albanose is undoubtedly 
the most abundant. 
Summing up the above, we may make the following roughly quantitative 
statement, in which the relative abundance of the subrangs, in the judgment of 
the writer, is that of the order in which they appear. It would be impossible to 
give more exact quantitative data without very minute and detailed study of all 
the districts. 
Order of Abundance 0} Subrangs. 
Abundant. Ciminose (II. 5. 2. 2), braccianose (II. 7. 2. 2), vicose (II. 6. 2. 2), vulsinose 
(I. 5 . 2. 2). 
Common. Albanose (III. 8.2.2), phlegrose (1.5.1.3), monzonose (II. 5. 2. 3), vesuvose (II. 8.2.2). 
Rare. Pulaskose (I. 5. 2. 3), auruncose (II. 5. 3. 2), harzose (II. 4. 3. 3), shoshonose (II, 5. 
3- S)> jugose (III. 7. 2. 2), beemerose (I. 6. i. 3). 
Very rare. Procenose (I. 6. 2. 3), fiasconose (III. 7. 3. 2), appianose (I. 7. i. 3). 
The reliability of these relative positions varies much. Thus the first four 
are undoubtedly easily the most abundant, but the orders of ciminose and brac- 
cianose, and of vicose and vulsinose, are open to question. The same is true of the 
"common" magmas, which collectively should follow the "abundant" ones, though 
there may be some question as to the relative abundance of albanose and phlegrose, 
