OF DENISON UNIVERSITY. 
131 
The remaining ingredients of the diorite, with the exception of the 
rather small amount of quartz, are more completely altered. The 
place of the plagioclase is taken by an opaque white amorphous sub- 
stance and the interstices are filled with granular light material. A 
few crystals of decayed augite are seen, which have large quantities 
of iron in stales and grains. Here and there grains of calcite indicate 
where some of the decomposition products have gone. There are ex- 
posed a few interesting masses of ilmenite, in which the hexagonal 
plates are matted obliquely, which show under the microscope the 
characteristic bronzy reflection. 
No. 1064 is essentially similar. It is a very tough, homogen- 
eous, greenish-grey rock. The actinolite is in the condition described 
above and the accessories are ilmenite, calcite, and apatite. It pre- 
sents to the eye the appearance of a fine-grained diorite, altering to 
serpentine. Irregular bands of a lighter colored rock occur in this 
mass. Such a specimen is No. 1065, which is a confused mass of 
finely granular material in which quartz, calcite and chlorite can be 
identified. Strings or veins of calcite are abundant, and scattered 
through the magma are many dark grains, the centres of which are 
generally filled by a single crystal of secondary calcite. 
No. 1066. This is the porphyritic phase before spoken of, which 
also contains the larger pebbles. Here and there in the section are 
large rounded grains of quartz, broken and intersected by the finely 
granular magma. The latter is not essentially different from the basis 
of 1065, but is crowded with rounded grains of oligoclase. Grains of 
secondary calcite and veins of the same, also pyrite and perhaps titan- 
ite are seen in the slide. It would appear that the magma is full of 
minute scales of chlorite, (Plate X, Fig. 2.) 
The only explanation suggested for the curious condition of the 
rock here is that the metamorphism was excessive and resulted in a 
thorough suffusion of the original slate with intrusive matter as well as 
pasty portions of the adjacent sediments, reducing all to a somewhat 
homogeneous character. The conglomeritic phases of the slate being 
rendered pasty, the pebbles were at first unaffected and were in- 
truded upon by the more fluid matter below. They were subjected to 
more violent flowage by reason of the obstinate pebbles during which 
the ingredients of the pebbles were partly set free and, although the 
magma was in part melted, the larger crystals remained dispersed in 
