804 HENRY S. WASHINGTON 
differ from the preceding chiefly in the structure, which is emi- 
nently trachytic. The minerals are much the same, and the 
feldspars differ only in habit. 
Two analyses of the nepheline-syenites were made, one of a 
specimen from Salem Neck west of the Fort, which was col- 
lected on the excursion of the Aq Ae TALS) in) Ausustetagar 
under the guidance of Mr. Sears; the other of a specimen from 
Great Haste Island, given me by that gentleman. The former 
is foyaitic in microstructure, the latter more ditroitic. Both are 
apparently quite fresh. Analysis III, of litchfieldite, is intro- 
duced for comparison. 
The two analyses resemble each other very closely, except 
that the former has more soda and less iron oxides. Compared 
with nepheline-syenites from other regions, the Salem rocks are 
notably poorer in lime and magnesia, and rather higher in silicathan 
most. In these respects they correspond closely to the nephe- 
line-syenites of Litchfield, Maine, and Red Hill, New Hamp- 
shire, described by Bayley,’ especially the former. This is an 
extremely albite-rich type, to which he has given the name of 
Litchfieldite. Bayley regards the orthoclase as secondary for 
the most part, but it is to be observed that, even if it owes its 
present form to secondary processes, it must have existed in the 
original rock. Although the composition of the ferromagnesian 
minerals in the Salem rock is not known with certainty, yet a 
rough estimate may be made of its mineralogical composition. 
This is given in Ia, the composition of the Litchfield rock as 
calculated by Bayley from good data being given in IIIa, It 
will be seen that there is much similarity between the two. 
la Illa la Illa 
Albite - - - 43. 46.9 Lepidomelane - Filet 6.9 
Orthoclase - = 2/20 Biotite, etc. - - 6 
Nephelite - - 20 i 7.0) Zircon, Magnetite,etc. 3 
Cancrinite - - I 2.0 
Pulaskitic Syenite.—In connection with the nepheline-syenites, 
and constituting a facies of them, are found rocks which 
t BAYLEY, Bull. Geol. Soc. Amer., Vol. III, p. 231, 1892. 
