:Dolhir Formation

{{Use dmy dates|date=April 2022}}

File:Gravicalymene arcuata.jpg

{{Infobox rockunit

| name = Dolhir Formation

| image =

| caption =

| type = Formation

| age = Ashgill Series

| period = Ordovician

| prilithology =

| otherlithology =

| namedfor =

| namedby =

| region = Wales

| country = United Kingdom

| coordinates =

| unitof =

| subunits =

| underlies = Mudstones of the Fron Frys Formation.

| overlies = Unconformable on various Caradoc Formations.

| thickness = 490 metres. Lateral variations, 320 - 490 metres.

| extent = Not defined

| area =

| map =

| map_caption =

}}

The Dolhir Formation is a geologic formation in Wales. It preserves fossils dating back to the Ordovician period.