Although Howchin publishing scientific papers throughout his career, his activity increased with age. In the last 30 years of his life his productivity was extraordinary for a man of his years; in 1933 the "Transactions and Proceedings of the Royal Society of South Australia" listed more than 100 of his papers. His most important work was on a series of glacial rocks, that he referred to as the 'Cambrian series' of the Mount Lofty Ranges, but are now known to be Permian, which gave rise to much controversy. For much of this later period of his life he was closely associated with another great Australian geologist of his era, Edgeworth David.