Additional Note on Boulders of Hornblende Picrite near the Western Coast of Anglesey

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Abstract
In a short communication printed in this Journal (vol. xxxvii. p. 137) I described a large boulder of hornblende picrite which I found near Pen-y-Carnisiog in the autumn of 1880. Last summer I had an opportunity of spending an afternoon upon the western coast of Anglesey, and made use of it to examine the interesting section to the south of Porth Nobla. I did not, however, neglect to look out for boulders, as I thought it not impossible that I might meet with some more picrite. In this I succeeded beyond my expectations, and now lay the results before the Society, together with some remarks on the microscopic structure of the specimens collected. After quitting the railway at Ty Croes Station, I walked a short distance along the road to the south-west, and then turned up a field-way leading past a small farm called Bryn Gwyn. A short quarter of a mile from it a boulder (No. I.), perhaps roughly trimmed, has been utilized as the capstone of a gate-post. It measures 2 3/4 × 2 × 1 1/4 feet. A small fragment projected, which I was able to detach for examination without injury to the stone. The next (No. II.) was a well-rounded boulder lying on the sandy shore at Perth Nobla. This had a rather greener matrix than those which I had previously seen: and the porphyritic hornblende or augite crystals were not quite so large. It measured about 2 feet each way, and rose about 1 foot above the

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