By the middle of the 1880’s Thomas was much in demand to lead expeditions for the various natural history societies which were springing up throughout the British Isles. His first and most frequent expeditions were with the Chester Society of Natural Science, with whose President the Cambridge Professor Thomas McKenny Hughes he had become closely associated as a knowledgeable and enthusiastic seeker after local fossils, some of which found their way into the collection of the Sedgwick Museum in Cambridge.
He had also become a favourite expedition guide for the Caradoc Field Club, a Shropshire Society based in Shrewsbury.
it is likely that McKenny Hughes or one of his associates had advised their using Thomas as a guide.
During 1885 Thomas guided major expeditions by both Societies, of which he gives full and fascinating accounts.
On 3rd August 1885 he accompanied members of the Chester Society to Glyn Ceriog – see here
Later that month he undertook a demanding two-day expedition for the Caradoc Field Club based on Dolgellau. A large party including some women, wives or relatives of the (all male) members, stayed ay the New Inn at Dolgellau overnight, and day one took in the summit of Cader Idris.
The full expedition can be viewed here
A photograph of the Chester Natural Science Society First long excursion,10–13 June 1898, Bull Bay, Anglesey (Siddall 1911). Some of Thomas’ friends appear, e.g. Dr. Stolterfoth, front extreme right. Mr. Siddall may be right centre, but since the caption suffers from a piece of Victorian everyday sexism the ladies’ names are omitted and therfore placement is uncertain.