
Between 1737 and 1766 Thomas Goldney III on several occasions managed to buy some of the adjacent property, which allowed him to carry out his plans for the development of the garden. He kept a Garden Book, which provides us with details of the work he undertook.
His first major project in 1737 was the construction of the Grotto. The first part of this scheme was actually to build a tunnel, so that he would not have to cross the public footpath leading through his estate (between two of the plots of land, which he had acquired). The Grotto itself was not completed until 1764. It is the finest surviving example of an eighteenth-century garden grotto in Britain. The walls and pillars are covered with a vast variety of minerals, shells, corals, rocks and fossils, some of which may have been brought back to Bristol by Captain Woodes Rogers. Its unusual design might have been influenced by Dutch styles of the late seventeenth century, and indeed Thomas Goldney II did visit the Netherlands in 1725, but it is unknown whether he was accompanied by his son.
The shells were completed in 1739 and the date is inscribed beneath one of the skylights. In the centre of the alcove sits a River God, occasionally referred to as Neptune, but as he has no trident and Bristol is situated on a river, it seems more appropriate that he be a River God. Opposite the entrance is the Lions' Den, containing an almost life-size plaster of Paris lion and lioness. The original Bathstone lion now sits on the terrace and was originally painted, in fact its resemblance was so striking that it frightened lady visitors.
No note describing the construction of the Bastion survives, but this mock fortification was certainly in existence by 1748. The west end of this provided a good view of the river and arriving ships. The Rotunda was finished in 1757, but presumably was begun substantially earlier. It was originally surrounded by a colonnade, but this was removed in the nineteenth century. It forms a link between the lower level of the Bastion and the higher level of terrace, and may originally have been used for fruit storage or as a summer house.
The canal was excavated in 1758-9, and the tower, built in 1764, was intended for Thomas Goldney’s Fire Engine. Steam power was used to pump water from the well supplying the cascade in the grotto and the fountain in the canal. It was a Newcomen steam engine, the first produced for non-industrial purposes by the Coalbrookdale iron works, and it took some time to get it working satisfactorily.