Angerthas Erebor was a version of the Runes used in the Third Age.
After the Second Age, the Cirth were made obsolete by the Tengwar among the western races and the Cirth remained in use only by Dwarves and Men. The Rohirrim and the Men of Dale used two related simplified forms. The Dwarves developed even pen-written cursive forms, since they used them exclusively in any form of writing communication, even in paper.
Thráin I came to Erebor and founded his dwarf-kingdom. There the Angerthas Moria were modified further and some new were added, but some reverted back to their Elvish usage, thus creating the Angerthas Erebor variation. This mode was used in Westron by Dwarves.
When Balin attempted to recolonize Moria, his followers used this script. The lower inscription of Balin's tomb is written in Westron, as well as the Book of Mazarbul.
The Angerthas Erebor showed revival of the $ and q but substituted R and T again for g and gh this time, or as variants to their original cirth.
The only innovations were only X and C for ps and ts.
The Book of Mazarbul shows some new cirth for vowel combinations and diphthongs.
An over circumflex indicates a long consonant while an under bar indicates a long vowel which means that the single cirth for the long vowels were not used at all. There is however a distinct letter for long ll