“ Dr. Williamson's views have often been controverted, but on the most important points he lived to see his conclusions accepted by almost all his opponents. In 1874 he received a Royal medal for his researches on fossil plants, which had then hardly more than begun. He also received the Wollaston Gold Medal of the Geological Society in 1890; he was a foreign member of the Göttingen Academy of Sciences, and the Royal Society of Sweden elected him to the place left vacant by the death of Dr. Asa Gray. Dr. Williamson's scientific work continued to the last. ”

“ In 1842 he began to practise medicine in Manchester, where for many years he pursued his profession with great success. During the whole of his busy professional career, however, he found time for constant scientific work. ”