In the month of June, 1789, Captain Watkin Tench, who, during his short sojourn in the infant colony showed himself as zealous in exploration as he was keen in his observations, started from the newly-formed redoubt at Rose Hill, of which he was in command, on a short excursion to examine the surrounding country.  This trip, inspired by Tench’s ardent love of discovery, became a noteworthy one in the annals of New South Wales.  It was made during the month that witnessed the discovery of the Hawkesbury River.  On the second day after his party left Rose Hill, they found themselves early in the morning on “the banks of a river, nearly as broad as the Thames at Putney, and apparently of great depth, the current running very slowly in a northerly direction.”

This river, at first known as the Tench, was afterwards named the Nepean by Phillip, when its identity as a tributary of the Hawkesbury had been confirmed.  Two other slight excursions were made by Tench in company with Lieutenant Dawes, who was in charge of the Observatory, and ex-surgeon Worgan.  In May, 1791, Tench and Dawes started from Rose Hill and confirmed the supposition that the Nepean was an affluent of the Hawkesbury, a matter over which there had been some doubt since its first discovery by Tench.  Tench returned to England in H.M.S.  Gorgon, in December, 1791.

The names of Paterson, Johnson, Palmer, and Laing are also connected with exploration on the upper Hawkesbury.

1.3.  The blue mountains:  Barallier.

The exploration of that portion of Australia which was accessible by the scanty means of the early settlers was for many years impeded by the stern barrier of the mountains, and most of their efforts in the direction of discovery were aimed at surmounting the range that defied their attacks.  Among the many whose attempts were signalised only by failure were the gallant Bass, whose name, for other reasons, will never be forgotten by Australians, the quarrelsome and pragmatic Cayley, and the adventurous Hack.  Amongst them there was one, however, whose failure, read by the light of modern knowledge, was probably a geographical success.  This was Francis Barallier, ensign in the New South Wales corps, who was encouraged by Governor King to indulge his ardent longing for discovery.  By birth a Frenchman, Barallier had received his ensigncy by commission on the 13th of February, 1801, having done duty as an ensign since July, 1800, by virtue of a government general order issued by Governor Hunter.  In August, 1801, he had been appointed by Governor King military engineer, in place of Captain Abbott resigned.  In February, 1802, he was succeeded by Lieutenant George Bellasis, an artillery officer.  Besides his expeditions to the Blue Mountains, he did much surveying with Lieutenant James Grant in the Lady Nelson.  In 1804, he went to England and saw service in several regiments, distinguishing himself greatly in military engineering, amongst his works being the erection of the Nelson Column in Trafalgar Square, the designer of which was Mr. Railton.  Barallier died in 1853.