The Doyle-Olligan partnership at Ballyknockan continued until Michael Doyle died in 1843. In his will, he left his share in the quarry 'half and half to John Brady and Patrick
Reilly. We can only assume Reilly and Brady were either married to his daughters, or were integral to the success of the business, or both.
By 1853 the partnership operating Ballyknockan had broken up and Patrick Olligan, John Brady and Patrick Reilly were running three separate quarries at Ballyknockan.
Patrick Olligan died unexpectedly in November 1853 leaving no will and no obvious successor. His eldest son, Michael, then aged 19, seems to have been involved in the business for the next few years and supplied the granite to Naas chapel in 1854-55, but disappeared from the records in 1856. Patrick Olligan's four other sons had no role in the business and it limped along for the next few years.
In the early 1860s an economic and building boom commenced and many other quarries opened up at Ballyknockan as new entrants tried their hand at the business. In 1861 Patrick Reilly sold his own quarry to Peter Bryan and purchased Olligan's quarry. This gave Reilly control of what was then the largest quarry at Ballyknockan.
In 1876 Patrick Reilly died and was succeeded by his son, Thomas M Reilly (also known as TM O'Reilly). TM O'Reilly's brothers were put to work in the quarry, but TM had been sent to Blackrock college for his education and inherited the quarry. It is said that he was more interested in writing and in the good life than in quarrying!
There was a financial crisis in Ireland in 1879. Very soon, this crisis led to the so-called 'Land War'. Many of the granite quarries in Ballyknockan went out of business including Reillys, which was surrendered to the landlord.
Against this bleak background, in 1880 William Osborne took out a lease on Reilly’s former quarry.
After this ignominious end to his quarry-owning career, TM O'Reilly took to writing and newspaper reporting and became a local representative. Thanks to his writings, and to his grand-daughter Rosie O'Reilly (c.1920 - c.2000), much of the lore of the early days of quarrying at Ballyknockan has come down to us.
Many years later, TM's sons, Peter and Patrick, both opened quarries in their own right:-