Further to the reply from Frances, I was sent the following information about the land and mansion a few years ago, but unfortunately I don't know from what publication it was extracted. I hope this helps.

"CITY , The Treen of Grenaby

City PR 1708

Citty BD 1793

The Cityn BD 1825

Citten OS
The land which at present comprises Glascoe was known as the City for most of its history. Two adjoining quarterlands were thus designated, lying on each side of the track South from Orry's Mount to Glascoe Beg and Nassau. The first quarterland, which has been called Glascoe since about 1790, was itself divided into two parts by the quarterland road. The Western part of this was owned by a family of Howlands from the late sixteenth century until 1804, when Thomas and Joney Howland, brother and sister, in their old age made over their property to their great-nephew Daniel Garrett of Andreas. The Eastern part, known as Clagh Bane, passed by inheritance in the female line from Goldsmiths in the seventeenth century to Crennells in the eighteenth, until the last Crennell, William, sold his land to his neighbour Daniel Garrett in 1810. The land South and West of Orry's Mount has been known as the City until much more recently and is still a recognised address on the Voters' List. Goldsmiths owned it in the seventeenth century and Howlands in the eighteenth, both families apparently unconnected with their neigbours mentioned above. Following the death of John Howland in 1788, the farm descended to his daughter Mrs. Margaret Cowle, and then to her grand-daughter Catherine Cowle, who married Thomas Caistill of Ballacamain, whose financial mis-fortunes were such that his wife's lands ss well as his own had to be made over for trustees to sell in 1823. The buyer of the City's 62 acres was James Kayll of neighbouring Grenaby, who, we believe, built the mansion house Orry's Mount on the land. Thomas Gibson, proprietor of Ramsey Shipyard, lived in the house for some time in the 1860s.
The present amalgamation of the two parts of the City had taken place by 1852 when Thomas Vondy, well-known farmer and businessman, was the owner and occupier. For most of this century the owners have continued to live in the mansion house, while the two old quarterlands are farmed together as Glascoe.
See Glascoe

GRENABY (Scan. GROEN BYR) Green farm

Grenby LA 1539

Grenaby BM 1739

Greenaby BM 1812
A Treen and one of its quarterlands.
From the beginning of the sixteenth century to the end of the nineteenth, Grenaby quarterland, with part of Ballacamain, was owned by one of the many Cowle families of the parish, and their descendants the Kaylls. The eldest son in most of the generations bore the Christian name Patrick, and the Wills of three of these Patrick Cowles (d. 1675, 1710, and 1759) bear witness to the family's abundance of stock and crop at home, as well as to their interest in fishing and in mountain sheep. The untimely death of Arthur Cowle, grandson of the last Patrick, at the early age of 26 in 1788, meant that for the next hundred years Grenaby was farmed by tenants,notable among them in the mid-nineteenth century Thomas Lace, a member of the Kerroo Doo family, well-known as a breeder of pcdigree stock.
Grenaby passed first to Arthur Cowle's sister, Catharine Thompson, and then to his second sister Leonora Kayll, whose grandson, Arthur Cowle Kayll, is given as the owner in Woods' Atlas. In 1841 the family was living at Orry's Mount, which they also owned, with its ground at that time known as the City. About 1890, Grenaby was the possession of William Burnyeat, but after his son John Burnyeat left the Island, the farm was bought by J. W. Vondy, whose descendant Dr. R. V. Kinnish is now the owner.
"