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Porphyry was observed on several spots; indurated clay frequently; and, on the top of the hill below which we encamped, I found quartz porphyry, and at the foot a psammite? which I had met several times associated with talc-schiste. April 21. We continued our journey in a S. 50 degrees W. course to latitude 19 degrees 13 minutes.
The country became still more mountainous; we passed, notwithstanding, many large well grassed flats, on which the timber grew to a greater size than we had observed it at the lower part of the river. The poplar-gum was very frequent in the hollow, and low stiff flats extended parallel to the river. The prevailing rock was talc-schiste, alternating with layers of psammite.
The country was in general open, with soft ground on the more extensive flats; although sandstone ranges approached the river in many places. Four good-sized creeks entered the river from the southward. The sandstone, or psammite, was composed of large grains of quartz mixed with clay of a whitish red or yellow colour; it frequently formed steep cliffs and craggy rugged little peaks.
Other conical hills or short ranges, with irregular rugged crests, were composed of granite of many varieties, red and white, fine grained without hornblende, or containing the latter substance, and changing into sienite; and, at one place, it seemed as if it had broken through Psammite. I observed quartzite in several localities, and a hard pudding-stone extending for a considerable distance.
The ranges were composed of a Psammite, which was frequently baked, probably by neighbouring out-bursts of igneous rock. Several familiar forms of plants were discovered; also a new Eucalyptus, with a glaucous suborbicular subcordate leaf, and the bark of the rusty gum: a stunted or middle-sized tree, which grew in great abundance on the ranges.
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