St Marcella’s Well
There are some wells high up in snow covered mountains, others lie in sun dappled, tree lined valleys. Some wells are so long forgotten that their location will never again be known, whilst other wells lie buried deep beneath roundabouts on the Denbigh bypass. Ffynnon Farchell, the holy well of St Marchell or Marcella, the Latinised form by which she is usually referred to, falls firmly into this final category.
Marchell was a daughter of Hawystl Gloff and Tywanwedd. She and two of her brothers, Deifyr and Tyrnog arrived in the area in the early 7th century; reputedly following the destruction of the great monastery at Bangor is y Coed by Ethelfrith in 613. They each set up neighbouring cells. Deifyr’s eventually became the parish of Bodfari and Tyrnog’s the parish of Llandyrnog. Marchell’s own parish was known as Llanfarchell up until the fourteenth century at which time Denbigh began to develop where it is now. Other of her brothers travelled further afield establishing churches on Anglesey.
The image of Marchell above is from a recently restored fifteenth century stained glass window in the church at Llandyrnog.
The guidebook to St Marcella’s church paints the fanciful picture of her arrival:
“Here on this very spot we can picture her raising her little shelter of twigs and osiers, her food such as she could gather from herbs, roots and berries and her drink, water of the spring which henceforth bore the name of Marcella’s Well or Ffynnon Farchell.” 
The present church dates from the fourteenth century, although the thirteenth century tower remains from an earlier building. Over time, with the movement of the population further west it has at times fallen into disuse and disrepair. During the Civil War it was used for stabling, and in the mid 1800s Lewis commented:
The ancient parochial church, dedicated to St. Marcellus, and now in a very dilapidated condition, is situated at Whitchurch, about a mile from the town, from which place the rectory was transferred by act of parliament to Denbigh, which was made the head of the parish. 
The church was restored in 1908 and is now in regular use. Its characteristic colour, being covered in white plaster, stands out in the landscape, and gives the area its name of Whitchurch (White church) or Eglwys Wen.
The well was located some 400 yards to the west of the church. It was recorded by Edward Lhuyd in his inventory of 1699.
“Ffynnon Fachell, near Whitchurch which is thought to be the Saint’s Well”
The uncertainty, even at this time, suggests that any traditions associated with the well were starting to become lost.
Eighteenth and nineteenth century writers, such as Pennant and Lewis, fail to mention it at all, suggesting again that most local tradition concerning healing traditions at the well had faded. However some memories of the significance of the well must have survived even at this period. Its use, maybe for bringing luck or as a wishing well are recorded by the Royal Commission on Ancient Monuments description in 1914.
The son of the old man who told me of the well informed me that as a boy he used to visit the well early in the morning after the great Denbigh fairs; and always found a number of coins which had been thrown into the well by passers-by. Once he discovered a half crown. 
The well finally dried up when the spring that fed it was cut during the construction of the Denbigh and Ruthin railway line in the late 1850s, so that by the time of the Royal Commission vsit in 1912 they reported that
There is no trace of it at present, except the channel which took the water away. 
The site of the well did continue to be recorded on Ordnance Survey maps up until the 1960s. This would suggest that it thus survived the building of the Myddleton Park housing estate, before it eventually vanished under the line of the bypass.
In visiting the well now the location identified below was based on these OS mapping records.
Let us assume that this represents Ffynnon Farchell, St Marcella’s Well.
Then our best estimate of where it was is as shown in the photographs below, just beside the roundabout on the bypass where you turn off towards Whitchurch
The image below is the church of St Marcella as viewed from the location of her holy well.
St Marcella’s feast day is celebrated on September 5th.
 R M (Bobi ) Owen (2010) St Marcella’s Church Denbigh – Guidebook
 Samuel Lewis(fourth edition, 1849) A Topographical Dictionary of Wales
 Royal Commission on Ancient and Historic Monuments (1914) An Inventory of the Ancient Monuments in Wales and Monmouth – Vol 4 County of Denbigh.